Add executor self-registration mechanism in the heartbeat service

[yahoNanJing]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

Currently when a scheduler restarts, we need to restart all of the executors, which is not so convenient.

Describe the solution you'd like

Add executor self-registration mechanism in the heartbeat service so that executors can register itself to the schedulers automatically through its heartbeat.

Describe alternatives you've considered

Additional context