CI of rel/0.12 is fixed

Hi, After fixing the CI problem in [1] The ci of rel/0.12 will not be blocked. If you have bug-fix pr to rel/0.12, please merge the rel/0.12 branch. [1] https://github.com/apache/iotdb/pull/3695 Thanks, — Jialin Qiao School of Software, Tsinghua University 乔嘉林 清华大学 软件学院

All thread pools are monitored and DO NOT USE Executors.newXXX() ANYMORE

Hi, We use many thread pools in IoTDB and it is hard to know how many thread pool we have totally and whether a thread pool is busy. Therefore, I unify the creation of ThreadPool, register it to JMX and allow JMX to check its active size, pending size, etc.. When the threadpool is `shutdown()` o

[BUILD-STABLE]: Job 'IoTDB/IoTDB-Pipe/master [master] [309]'

BUILD-STABLE: Job 'IoTDB/IoTDB-Pipe/master [master] [309]': Is back to normal.

Re:All thread pools are monitored and DO NOT USE Executors.newXXX() ANYMORE

Decent work! The use of threads is also messy in the iotdb-cluster module. We can continue to optimize based on this pr. However, this requires code submitters and reviewers to ensure do not use `Executors.newXXX()` FUNCTIONS ANY MORE IN THE FUTURE. It would be better if a code detection tool