[Feature]: Support placement groups for elastic fleets

[r4victor]

Problem

Part of #2973

Currently placement groups are created and used by process_instances() when creating new instances for non-elastic fleets via Compute.create_instance(). Dynamic instance provisioning on job submission (on run apply) in process_submitted_jobs via Compute.run_job() does not create or use placement groups, which effectively means placement groups are not used for elastic fleets.

Solution

Support placement group creation and use in process_submitted_jobs similar to process_instances.

Workaround

No response

Would you like to help us implement this feature by sending a PR?

Yes