gateway / scheduler refactor protptype

[akihikokuroda]

Summary

Prototype for #1033

Details and comments

This is on top of PR #1077. The changes for this prototype are in the last commit.

The changes are:

1. wrap the entry point sent to Ray. it sends a notification to the gateway when the entry point completes execution. It eliminates the polling of the ray job status.
2. put a signal listener for Job db changes. It can check if a Job to be scheduled and it some resources to be cleaned up.

[akihikokuroda]

This is a quick prototype. There are a lot of things to clean up. Please take look. Thanks!

[IceKhan13]

ok, I think we need to have some kind of development branch to merge dependent PRs there. Otherwise we have bunch of PRs that sits in queue and we develop over them, while we should develop independently

[akihikokuroda]

I can make this independent (based on the current main). It can show better what are changes.

[psschwei]

I can make this independent (based on the current main).

big +1 for this 😄

[akihikokuroda]

PR is recreated based on current main branch in #1084. Closing.