* Small documentation improvements and clarifications around AuthN / AuthZ

* PR feedback and added some clarifications

Motivation
The state is not production-ready.

Modifications
Remove the note about stateful function from the Deploy a cluster on bare metal document.

updated docs for releases: master ~ 2.1.0

Fixes #7895

### Motivation
For get-internal-stats of persistent topic admin cli: https://pulsar.apache.org/docs/en/2.6.0/admin-api-persistent-topics/#get-internal-stats, we can also return the compacted topic ledger id if compaction is enabled. So we'll able to read from ledger without creating additional subscription, it can benefit like querying compacted topic from Pulsar SQL.

### Modifications
Expose CompactedTopicContext from CompactedTopicImpl, try to get ledger information of compacted topic ledger if exist in PersistentTopic.

### Verifying this change

This change added tests and can be verified as follows:
- Added unit test to verify correct compacted ledger info is returned after compaction.


* Report compacted topic ledger info when calling get internal stats.

* Update documentation to add information about returning compacted topic ledger when get-internal-stats.

Add bookkeeperClientMinNumRacksPerWriteQuorum, bookkeeperClientEnforceMinNumRacksPerWriteQuorum conf options (#7977)

Added bookkeeperClientMinNumRacksPerWriteQuorum and bookkeeperClientEnforceMinNumRacksPerWriteQuorum to be able to configure rack and region aware bookie selection policy more precisely.

Motivation
We have Apache Pulsar setup running on Azure in 3 different Availability Zones (2 bookkeepers per zone). We wanted to store copy of each pulsar message in all that AZs. After configuring rack aware bookie selection policy, we found that messages are usually stored only in 2 AZs. After digging, we've found that it's caused by default bookeeper client minNumRacksPerWriteQuorum=2 setting. We've added bookkeeperClientMinNumRacksPerWriteQuorum and also bookkeeperClientEnforceMinNumRacksPerWriteQuorum to be able to configure this behaviour.

Modifications
Added bookkeeperClientMinNumRacksPerWriteQuorum and bookkeeperClientEnforceMinNumRacksPerWriteQuorum configuration option, modified tests, config files and documentation.

Verifying this change
We've updated existing unit tests, deployed modified pulsar docker image on AKS kubernetes cluster using helm charts and checked that stored messages were written always to bookkeepers in all AZs.


* Added `bookkeeperClientMinNumRacksPerWriteQuorum` and `bookkeeperClientEnforceMinNumRacksPerWriteQuorum` broker configuration options to be able set `minNumRacksPerWriteQuorum` and `enforceMinNumRacksPerWriteQuorum` bookkeeper client options.

* Reverted accidental change in ServiceConfigurationTest.
Co-authored-by: NMichal Koziorowski <Michal.Koziorowski@tomtom.com>

* Add docs of package Pulsar Functions
Signed-off-by: Nxiaolong.ran <rxl@apache.org>

Motivation
Website admin cli link error
Modifications
Update link version
Verifying this change
Local test

Co-authored-by: NTakesi Kimura <takeshki@yahoo-corp.jp>

[Issue 7864][docs]Update document for how to pick active consumer for failover subscription. (#7917)

Update document to specify how active consumer is picked for partitioned and non-partitoned topic for failover subscription mode. The change was push in 2.4.2 but document has not been updated.

Fixes #7864

**Motivation**

After #7813, the python client supports the oauth2 authentication as well. Add an example for it.

* Add Pulsar Summit CFP blog

* update

* Update 2020-08-25-pulsar-summit-asia-2020-cfp.md

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

### Modifications

Fix the time of release 2.6.1 to `08/21`

Fixes #7481

Motivation
Default bookkeeper conf that ships with apache pulsar indicates that the unit of openLedgerRereplicationGracePeriod is in seconds, but official bookkeeper doc(and code) mentions that the unit is in milliseconds.

Pulsar should configure default as 30000 instead of 30 and bookkeeper.conf should mention that the unit of this period is milliseconds instead of seconds.

Modifications
Update the bookkeep.config file
Update the following Pulsar docs for releases 2.5.2, 2.6.0, 2.6.1, and master
Reference > Pulsar Config > BookKeeper

Update AWS deployment in reference-configuration.

### Motivation

 PR (https://github.com/apache/pulsar/pull/7821) supports set/get/remove the deduplication policy at the topic level. 


### Modifications

Update the doc based on code updates.

The following docs are updated:

- Messaging: message deduplication
- Manage message deduplication
- pulsar admin cli reference

Modifications
Sync the Pulsar project description with the latest version on home page.

* add 300 contributor blog

* update

* update

* update

* update date info

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

### Modifications

Add release 2.6.1 blog for the website.

Signed-off-by: Nxiaolong.ran <rxl@apache.org>


### Modifications

Use the 2.6.1 version of the docs as the latest stable version

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

### Motivation

Currently, when the official website 2.6.1 document is released, we should first let 2.6.0 continue as the default version, wait for version 2.6.1 to appear in the historical version, and then try to use version 2.6.1 as the default version. If we directly publish the 2.6.1 version of the document, the search function will be unavailable.

### Modifications

- Update versions.json

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

### Motivation

Currently, the 2.6.2 docs are a complete copy based on 2.6.1. In the next pull request, if there is a fix for the 2.6.2 document, we can modify it based on the current 2.6.2, so A release manager can directly reuse the contents of the 2.6.2 document when releasing 2.6.2


### Modifications

- Add docs of 2.6.2
- Add sidebars of 2.6.2

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

### Motivation

Update 2.6.1 docs

### Modifications

- update 2.6.1 docs
- add 2.6.1 sidebars.json
- update releases.json
- update versions.json

Signed-off-by: Nxiaolong.ran <rxl@apache.org>

### Modifications

- Add 2.6.1 release notes to repo

Motivation:
The resource page is out of date.

Modification:
1. The tech blog of the same series are put next to each other.
2. The shared slides are updated.
3. The Bot WeChat ID is added on contact page.

* Fix admin-api-namespaces page grammatical errors

* Resolve review comments

This PR fixes admin-api-partitioned-topics page grammatical errors.

### Motivation
In #7699, i update doc for the master only. The contents are approved and merged.

This PR is for updating docs for releases 2.6.1 --2.1.0



### Modifications

Update the following docs:

Pulsar IO > get started
Connector Admin CLI

### Motivation

Adding a subdirectory associated with current time willmake it easier to process HDFS files in batch.

For example, user can create multiple running sink instances with `yyyy-MM-dd-hh` pattern. Then stop all instances at next hour. Eventually, files of the subdirectory will contain all messages consumed during this hour.

### Modifications

- Add a `subdirectoryPattern` field to `HdfsSinkConfig`
- Update some simple tests for `HdfsSinkConfig`
- Update the doc of HDFS2 sink

### Documentation

  - Does this pull request introduce a new feature? (yes)
  - If yes, how is the feature documented? (docs)

* update source create description

* update as per advice from sijia

Motivation:
Update the resources page.

Modification:
Some blogs are added.

* add deploy-docker doc

* Update deploy-docker.md

* Update site2/docs/deploy-docker.md
Co-authored-by: NJennifer Huang <47805623+Jennifer88huang@users.noreply.github.com>
Co-authored-by: NJennifer Huang <47805623+Jennifer88huang@users.noreply.github.com>

### Motivation
I tried to follow the Aws deployment guide at https://pulsar.apache.org/docs/en/deploy-aws/ but found it was pretty outdated - It was trying to install pulsar 2.1.0-incubating. This PR updates it to install 2.6.0.

### Modifications

* Updated the pulsar version to 2.6.0
  * Fixed download location for 2.6.0
  * Updated config files for 2.6.0
  * Fixed connector installation for 2.6.0
  * Fixed Ansible's yum warning about installing multiple packages

Fixes #6109

### Motivation
Tell user the available values of "--sink-type" "--source-type" parameter of the Cassandra built-in connector.

### Modifications
Update the following docs:

- Pulsar IO > get started
- Connector Admin CLI

Currently, only docs in master is updated. After the PR is approved, versioned docs will be updated also. So, do not immediately merge the PR when it is approved.

* Update functions-worker.md

* Update functions-worker.md

* Update site2/docs/functions-worker.md
Co-authored-by: NJennifer Huang <47805623+Jennifer88huang@users.noreply.github.com>