MultiKueue: Support Elastic RayJob

[mimowo]

What would you like to be added:

I would like to support elastic RayJob via MultiKueue.

The main problem with the current approach of Workload a the RayCluster level is that we only create the instance of RayCluster on the worker cluster, thus:

1. there is no RayJob instance to create the RaySubmitterJob on the worker cluster

Why is this needed:

To run Elastic Ray Job via MultiKueue.

[mimowo]

/assign @highpon
cc @yaroslava-serdiuk
Who is already working on that

[mimowo]

cc @andrewsykim

[mimowo]

related to #8201 , actually this is going the opposite way

[hiboyang]

Working on PR 8341 related to this issue.

Previously we discussed to make RayCluster always top level and remove RayJob integration. Turned out that did not work with MultiQueue. In MultiQueue, we need to manage RayJob in Management Cluster, and copy it to Worker Cluster.

There are also other changes needed, see details in PR 8341.

[olekzabl]

/area multikueue