Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Upgrade dependencies and make the JDK11 compiling passed.

* Update license and fix license check file.

* Add CI for JDK11 compiling.

* Update doc.

* support build single module

* enforce maven version must greater than 3.6

* update build doc to support maven3.6+

Modify Eclipse and IDEA  steps

* Make an alternative method while cloning skywalking project and sync submodules

* Add language type for code block

* Intend code blocks under list block

* Make list number same

* Move a tip about building from source codes.
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* mvnw proxy config

explanation about config proxy mvnw
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Add es7 support to docker

* Add es7 to github aciton workflow

* Rename dockerfile

* Update docker-compose

* Update matrix es name

* Set oap tag

* Add document

* Update How-to-build.md

* 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

* 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

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

* 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

* 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.

* Move oal tool back into main repo, and fix compile issue.

* Fix two bugs.

* Remove all generated codes.

* Make all oal generated codes out of source control.

* Make mvn compile and package work.

* Fix test cases.

* Make compile right and provide new documents.

* Remove an unnecessary tokens file.

* Lock oracle and resin plugins version.

* Move resin and oracle plugin to openskywalking

* Restore submodule active.

* Add another submodule active command.

* Remove the wrong test cases in release and fix some doc issues.

* [maven-release-plugin] prepare release v6.0.0-alpha

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

* Fix some doc

* update build md

* add   generated-sources  protobuf  in  build.md

* Moves to Maven wrapper to stabilize the version in use

This will ensure those building will have similar experience due to
having a fixed maven version.

* Updates most plugin versions and removes redundant configuration

* Sets up build enforcement for JDK 1.8 until further work occurs

* Update How-to-build-CN.md

* Update How-to-build-CN.md

* Update How-to-build.md

* Update docs for alpha release

* Delete a comma.

* Update How-to-build.md

* Add data-set licenses file

* Rename LICENSES-data-set to LICENSE-data-set

* Update LICENSE

* Remove fastclick from LICENSE

* Make the git submodule command to be a maven profile plugin. Let this command not execute by default install command.

* [maven-release-plugin] prepare release apm-5.0.0-alpha

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

* Product name is not correct

* Add more documents for release.

* Change profile id.

* Add CHANGES file in distribution file.

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

This reverts commit ac815019.

* Revert "[maven-release-plugin] prepare release apm-5.0.0-alpha"

This reverts commit 095597c9.

* Add rat plugin to check dependency license and add license head into missing files.

* Fix docs.

* Exclude web ui config file.

* Next release guide.

* UI update.

* Update docs.

* Build source shell.

* Update docs and source release.

* remove .sha256 requirement.

* Update How-to-release.md

* Update How-to-release.md

* Update build doc.

* Update docs.

* Update How-to-release.md

* Update How-to-release.md

* Update docs for alpha release

* Delete a comma.

* Update How-to-build.md

* Add data-set licenses file

* Rename LICENSES-data-set to LICENSE-data-set

* Update LICENSE

* Remove fastclick from LICENSE

* Make the git submodule command to be a maven profile plugin. Let this command not execute by default install command.

* [maven-release-plugin] prepare release apm-5.0.0-alpha

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

* Product name is not correct

* Add more documents for release.

* Change profile id.

* Add CHANGES file in distribution file.

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

This reverts commit ac815019.

* Revert "[maven-release-plugin] prepare release apm-5.0.0-alpha"

This reverts commit 095597c9.

* Add rat plugin to check dependency license and add license head into missing files.

* Fix docs.

* Exclude web ui config file.

* Next release guide.

* UI update.

* Update docs.

* Build source shell.

* Update How-to-build-CN.md

* Update How-to-build.md

Remove OJDBC and resin artifacts from ci-dependencies driectory as they as not Apache license compatible.
The user can onetime manually download them, and the maven reactor will automatically build the corresponding plugins.

OJDBC is OTN which requires a user click-through agreement.
Resin is GPLv3, meaning any derivative work must also be GPLv3 licensed.
https://www.apache.org/licenses/GPL-compatibility.html

ref: https://github.com/apache/incubator-skywalking/pull/737