* #2183

Merge commit into master.

* Make the h2 register lock same as mysql.

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

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

correct spelling error.

* Update trace-mode-grafana.json

Update heatmap expression

* Update trace-mode-grafana.json

* Update mesh-mode-grafana.json

fix bugs for more than one instance

* Update mesh-mode-grafana.json

Fix heatmap

* fixed  the index name to format name in logs

* modify the log level from info to debug

* Update ReferenceIdExchanger.java

Change comments of codes.

* 🎉 PHP agent

* Update powered-by.md

Change user list order

* Refactor service instance inventory to properties based entity.

* Fix a bug and refactor properties update.

* support overview-cn.md translation

* update overview-cn.md translation

* update fix error statement problem

* update fix error statement

* plugin support redisson

* Add properties for service inventory

* Fix code bugs

* Provide develop doc for inventory extension.

Add 5 new users based on #443

* remove duplicate config in docker.

* Revert "remove duplicate config in docker."

This reverts commit eb774035

* update content.

* 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

* Finish the basic codes of telemetry.

* Add many telemetry in oap.

* Fix a test case.

* Finish all telemetry metric.

* Fix format.

* Make telemetry works.

* Support JVM metrics.

* Add doc for telemetry.

* Fix typo.

* Fix #2135

* Finish the APIs of telemetry module.

* Add prometheus license.

* Active default telemetry provider.

* add ojdbc component id

* Support Gson plugin

* Update submodule skywalking-ui

* Update submodule skywalking ui