* Add envoy metrics service protos

This patch imports protos from envoyproxy/data-plane-api and
prometheus/client_model to enable metrics service service feature in
SkyWalking OAP.
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Add Envoy related docs
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Update the LICENSE to include new protos license

From:
- envoyproxy/data-plane-api
- prometheus/client_model
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Add a complete config.yaml example
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Add note on Envoy dynamic config
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Add protoc-gen-validate license
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Add samples
Signed-off-by: NDhi Aurrahman <dio@tetrate.io>

* Make CI and license right.

* Update README.md

@dhi typo :P

* Update README.md

Another typo :P

* Delete metrics.json

metrics.json is included in identify.json and not be linked in document.

* Update and rename Spring-bean-plugins.md to Spring-annotation-plugin.md

* Update README.md

* Update README.md

* Make scope meta configurable.

* Fix test cases in ci.

* Change step 1

* Refactor step 2

* Other compile issue done. Prepare the generator changes.

* Revert some wrong changes to Istio receiver.

* Step 3, make compile pass.

* Try to make CI passed.

* Add a check.

* Fix generated code style

* Provide new and extendable dispatcher generator tool

* Fix startup.

* Can't guarantee the dispatchers are always existing. Put explicit comments at there to avoid confusion, since this is different with old version.

* Fix a H2 query for endpoint search.

* Fix a wrong mysql alarm query.

* Provide new document and `generate-tool-grammer` module.

* Add missing last section of document.

* Fix typo

* Relocate the @ScopeDeclaration annotation, make it more sense. Also remove the useless @SourceType annotation. And adjust document for these changes

* ScopeDeclaration can be used once for each class only, now.

[Performance Improvement]Backend streaming thread model improvement

* Zookeeper plugin

* Support to register different host/port at cluster coordinator. Only for Zookeeper and Consul

* Provide document for internalComHost and internalComPort

* Reset port to default.

* Make sure all document images ref from our Apache website.

* Change the statement.

* Set dist bin tar with -bin in the final name.

* Change dockerfile and makefile

* Support lettuce plugin

* lettuce plugin bugfix

* lettuce plugin fix license issue

* lettuce plugin fix cluster and config issue

* plugin lettuce compatible with low 5.0.x version

* lettuce plugin support version accurately describes on Supported-list.md

* plugin lettuce compatible with low 5.0.2 version

* lettuce plugin fix wrong batch method intercept point

* move lettuce to optional plugins

* fix ci issue

* fix ci issue

* Modify the description file

* Pom code optimization

* Optimization operation name

* Optimization operation name2

* fix gRPCHost

* fix gRPCHost

correct spelling error.

* Update trace-mode-grafana.json

Update heatmap expression

* Update trace-mode-grafana.json

* Update mesh-mode-grafana.json

fix bugs for more than one instance

* Update mesh-mode-grafana.json

Fix heatmap

* 🎉 PHP agent

* Update powered-by.md

Change user list order

* plugin support redisson

* Add properties for service inventory

* Fix code bugs

* Provide develop doc for inventory extension.

* Change a label name for  sw instance to avoid confict.

* Fix a wrong metric name.

* Fix too many counter instances.

* Set uptime to second.

* Fix format.

* Fix format

* Remove two unnecessary counter.

* Provide grafana dashboard settings and remove unnecessary metric.

* Provide a simple UI brief doc. Fix #2137

* Finish the basic codes of telemetry.

* Add many telemetry in oap.

* Fix a test case.

* Finish all telemetry metric.

* Fix format.

* Make telemetry works.

* Support JVM metrics.

* Add doc for telemetry.

* Fix typo.

* Fix #2135

* Support Gson plugin

* Update README.md

* Update README.md

* Fix doc.

* Fix typo

* fix classloader dead lock in jdk7+

* support springcloud fegin 2.x

* update pom

* fix checkstyle

* fix checkstyle

* Update pom.xml

* cn doc

* cn doc

* cn doc

* cn doc

* cn doc

* delete cn default readme

* Update How-to-release.md

The public gpg file name should be KEYS, not KEY. It will contains other PMCs public key in this file after you export from the gpg tools.

* Provide consul cluster plugin.

* Change log and application config file.

* Add consul's config item into the docker's application.yml.

* Fixed bug.

* Add consul description into  readme.

* Add okhttp component license.

* Support webflux and spring mvc 5 plugin

* Change instrumentation

* Change instrumentation

* fix check style

* Add support 2.1.x instrumentation