* [Feature-4355][Master-Worker-API] improvements of master and scheduler module (#6085)

* master refactor:
   1. spi for task submit and other actions(pause, kill)
   2. remove threads for process instance and task instance.
   3. add events for process instance and task instance

* ut npe

* add try catch

* code style

* fix critical bugs

* fix critical bugs

* fix critical bugs

* fix critical bugs