* [maven-release-plugin] prepare release v8.8.0

* [maven-release-plugin] prepare for next development iteration

* Create changes-8.8.0.md

* Reset changelog for 8.9.0

* Remove agent codes and clean up

* [maven-release-plugin] prepare release v8.7.0

* [maven-release-plugin] prepare for next development iteration

* [maven-release-plugin] prepare release v8.4.0

* [maven-release-plugin] prepare for next development iteration

* [maven-release-plugin] prepare release v8.3.0

* [maven-release-plugin] prepare for next development iteration

* [maven-release-plugin] prepare release v8.2.0

* [maven-release-plugin] prepare for next development iteration

* Upgrade dependencies and make the JDK11 compiling passed.

* Update license and fix license check file.

* Add CI for JDK11 compiling.

* Update doc.

* Add a muse configuration file

A muse configuration and file is necessary to educate the MuseDev CI
system on how to build Skywalking.

* Exclude .muse/* files from license check

* support build single module

* enforce maven version must greater than 3.6

* update build doc to support maven3.6+

* [maven-release-plugin] prepare release v8.1.0

* [maven-release-plugin] prepare for next development iteration

Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* [maven-release-plugin] prepare release v8.0.0

* [maven-release-plugin] prepare for next development iteration

* Remove all shardingsphere cases.

* Fix license headers and rename E2E job name

* Fix RAT plugin and enable both RAT and checkstyle plugin

* [maven-release-plugin] prepare release v7.0.0

* [maven-release-plugin] prepare for next development iteration

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

* Enable OAP gRPC SSL transportation

Porting to OpenSSL to enable SSL transportation. The server private
key is in the format of PCKS#8, certificates is x509 though.
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Add netty-tcnative-boringssl-static 2.0.26 licnese
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Update docs/en/setup/backend/grpc-ssl.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@apache.org>

* Update docs/en/setup/backend/grpc-ssl.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@apache.org>

* Add SSL to grpc remote client and sharing server
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Update documents
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Fix nits
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Fix test case
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Add e2e-ssl and remove other test cases temporarily
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Add TLS relevant files
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Decrease timeout
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Test config works
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* triger CI on oap-ssl branch

* Disable agent ca
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Switch to sharing server
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Add agent log to console
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Upload log files

* Change backend
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Revert "Change backend"

This reverts commit 7a085711e3653d3bf642aa84f73650e22595e383.

* Update backend
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Revert e2e
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Ignore TSL relevant files
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Polish codes
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

* Update certificates expires year to 2120
Signed-off-by: NGao Hongtao <hanahmily@gmail.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>
Co-authored-by: Nkezhenxu94 <kezhenxu94@apache.org>