* Rabbitmq plugin e2e test migration

* 3753-code review fixes

* 3753-test-case-improvements

* Update pom.xml

Remove the repo addresses.

* Update Plugin-test.md

* immigrate test feign scenario.

* add license.

* update use test skeleton.

* delete repeat spring-boot starter dependence.

* add support-list version.

* Add elasticsearch 6.x plugin & elasticsearch 6.x test scenario

* jedis scenario

* update doc

* fix archetypes

* fix log4j

* provide archetypes for testcase

* merge undertow scenario

* update elapsed time

* Add SkyWalking plugin test framework doc

* Remove Chinese.

* Add a description to the env variable, CASE_SERVER_IMAGE_VERSION

* Fix typo

* Change paragraph structure.

* Polish doc, remove old OAL description.

* Add a new use case.

* Committer vote and set up document.

* Change document link structure.

* Fix typo.

* Remove the meta file

* Add dependency licenses check 

* POC: Intercept successfully.

* Refactor codes

* Build the new core

* Setup the new core.

* Push the javassist version to 3.23.2-GA, as it is the last version supports JDK 1.6 compile, according to https://github.com/jboss-javassist/javassist/blob/rel_3_23_2_ga/pom.xml#L149-L160

* Finish the all codes.

* Document updated for bootstrap instrumentation.

* Add a notice to document.

* Remove unexpected file.

* Set javassist version right. Add judge in core interceptors

* Fixe no log bridge implementation

* Change OAL generator tool to runtime.

Step 1. change project structure. API links and maven pom.

* Part of metrics class generation

* Metrcis class generated.

* Set up the basic structure of new OAL engine.

* Finish metrics generation.

* Support dispatcher generation.

* Format codes.

* Generate dispatcher all methods.

* Implement disable in hardcode.

* Clear up

* Fix compile startup.

* Update license and document of new OAL engine.

* Fix rat.

* Disable class output in default

* Copy from @kezhenxu94 's test PR, https://github.com/apache/skywalking/pull/3110

* Wait for the mount command to finish

* Add docs of e2e development guide

* setup your idea

* add anchors

* fix

* Update docs/en/guides/How-to-build.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@163.com>

* Update docs/en/guides/How-to-build.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@163.com>

* Adjust pom plugin position and add docs

* Polishing

* Update as requested

* Implement the base of config API module.

* Finish configuration module codebases w/o tests, revert some changes.

* Finish mock tests.

* Add new gRPC service for configuration.

* Make gRPC configuration sync provider works.

* Add database slow statement dynamic setting.

* Finish the dynamic configuration service.

* Fix version.

* Update docker building of oap server

 * generating appliation.yml according to enviroment variables
 * adding Makefile to build binary and docker image

* Update ui docker

* Update docker-compose

* Update document

* Update document

* Merge from master

* Reset skywalking-ui

* Rename metric to metrics.

* Fixed test case execute failure issues.

* Introduce new profile in release

* Fix a missing change.

* Fix wrong profile name.

* Move submodule plugin.

* Always auto-submodule

* [maven-release-plugin] prepare release v6.1.0

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

* Change keys location.

Update all "incubator-skywalking" to "skywalking" ,"incubator-servicecomb-java-chassis" to "servicecomb-java-chassis" correctly, and ".gitmodules" will update at #2531 (#2548)

* Set RocketBot as primary UI in doc

* Update submodule.

* Move all receiver proto files together, in case the class conflict in gogoproto.

* Add jaeger proto and its dependency proto. Also license provided.

* Fix rat.

* Support grpc exporter.

* Support scope(all) metric export and finish document.

* Close exporter even in local debug env. And fix CI.

* Remove the system.out

* Fix absent 4.

* Support subscription from remote.

* Add the doc

* Update application.yml