* Add config to control tracing sql parameters

* restore solrj-plugin

* restore solrj-plugin

* Revert SolrJ plugin.

* Remove an unexpected test case.

* Revert "Remove an unexpected test case."

This reverts commit 359990e18b0c0ae1a6e1005ff985bf237ec05619.

* Clear context.

* Fix a leak.

* new branch for solrj-plugin

* rollback and add module solrj-plugin

* preparing to pr

* to resolve reviewers' suggestions

* remove unused code

* remove unused code

* remove unused comments

* To avoid NPE

* fix typo

* Change to JRE6

* fix pom.xml merge incorrectly. and java.net.URL instead of Regex

* Using RuntimeContext instead of ThreadLocal

* To reduce unnecessary tags

* add test cases

* fix validation fail

* add solrj-plugin into component-libraries & Supported-list

* to trace all patch to avoid recheck status of span

* remove unnecessary properites

* remove unnecessary tags

* Add the config to document of setup

* spring cloud gateways plugin

* Submit custom enhancement kernel code for the first time.

* Submit the code again.

* Optimize ClassUtil code.

* Submit custom enhancement plugin code for the first time.

* To fix CI issue.

* To fix CI header Tmp issue

* To fix CI Tmp header issue

* Customize plugin code submission

* Add md file.

* Fix some bug.

* Fix ci issue

* Fix md desc

* Fix unapproved license

* Fix bug

* Fix collection bug.

* Fix java8 pair ref issue

* Fix CI issue.

* Add more detail for expression.

* Fix review issue

* Fix review issue 2

* Fix review code issue 2

* Fix md issue

* Fix bug and op desc md.

* Update customize-enhance-trace.md

* Update customize-enhance-trace.md

* FIx code review issue.

* add instance id configuration item

* add doc about instance uuid

Make supported list more clear.

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

* Update README.md

* Update README.md

* Zookeeper plugin

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

* Change the statement.

* 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

correct spelling error.

* Support Gson plugin

* Update README.md

* Update README.md

* feat:Active System.env Config In Both Collector And agent.config.
1、moving related codes into apm-util module.
2、update Setting-override.md about how to use.

* resolve docs.

* typo

* finish test case.

* Update README.md

* Update new protocol

* Support new protocol at agent side.

* Fix test case.

* Make backend supports new trace protocol

* Fix tests.

* Make all new services available in gRPC.

* Fix bugs.

* Finish new document for v2 trace protocol.

* Fix wrong version requirement of zk

* Fix trace query bug.

* Find a client side dictionary bug.

* Fix register bugs.

* Fix break doc links.

Fix typo

* Replace v5 changes by a link to 5.x branch. New v6 changelog.

* Finish query doc and fix a missing field in alarm doc.

* Add link to official oal in alarm doc.

* Fix words.

* Fix some doc

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Support alarm message.

* Fix document words.

* Support alarm hook.

* Fix javadoc issue.

* Sync submodule

* Sync submodule

Refactor documents. Delete all backend documents, cc @peng-yongsheng , considering backend refactored, then the documents should rebuild manually.