* 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
* Change a label name for sw instance to avoid confict.
* Fix a wrong metric name.
* Fix too many counter instances.
* Set uptime to second.
* Fix format.
* Fix format
* Remove two unnecessary counter.
* Provide grafana dashboard settings and remove unnecessary metric.
* Provide a simple UI brief doc. Fix#2137
2. Make service relation and endpoint relation to record component id.
3. Delete service mapping indicator.
4. Make service inventory to record mapping service id.
5. Refactor global topology query and service topology query.
* 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