Motivation:

According the feedback from the community, the e2e tests are hard for
them to understand and get them started, so this pull request aims to
rewrite the e2e tests with some improvements:

- debuggable locally, now you can run every individual case directly
inside the IDE, just like running a plain unit test.

- same functionalities of multiple counterparts share the same codes,
cases like different storages and cluster coordinators share the same
codes, easy to add more similar cases.

- the "end" now extends to the Doccker images, meaning that some bugs
like #4483 and #4471 can be more easily and early to be discovered.

- codes style and license headers are checked

Modifications:

- adopt jupeter (a.k.a junit 5), testcontainers as the new test
framework, all containers are orchestrated by docker-compose.yml,
well-known technology that developers should be familiar with.

- rewrite all test cases and verify them.

- reorganize the workflows in GitHub Actions.

Result:

- new e2e test should be easy to add.

- closes https://github.com/apache/skywalking/issues/4472

* support docker-compose

* sync

* support docker-compose

* force rm container

* solrj-7.x-scenario

* fix license header

* fix actualData.yml

* verify Jenkins run on distribution

* test Jenkinsfile v2

* test Jenkinsfile v3, God bless

* test V4, God Bless

* test v5

* rollback

* update opertaion of post

Provide the codebase of plugin tests. Make the plugin test in the CI loop.

* Check license header strictly

* Ignore header template

* Include more files to check list

* Remove login permanently.

* Sync UI change.

* Delete `org.apache.skywalking.apm.webapp.security`

* Delete tests.

* Update webapp to support rocketbot

* Revert pom.xml

* Update webapp for rocketbot ui

 * Add NotFoundHandler to handle SPA url routing
 * Update ui dockerfile with tlp tar name

* Update webapp to support rocketbot

* Revert pom.xml

* Add more documents for v6.

* Make default setting consistent .

* Remove backend service discovery

* Add undefined node icon

* Add login filter

Username and password are stored in application.yml with
prefix "security.user"

* Modify startup script and add webapp.yml config file

* Update quick-start document for default login username/password

* Update deploy document for new webapp.yml config file

* Update license for new files.

Fix IPMC checks for releasing.