feat: inject job info as envvars in scheduled pods

[dejanzele]

What type of PR is this?

Feature PR which injects two environment variables into all containers of gang-scheduled jobs when they have node uniformity requirements:

• ARMADA_JOB_ID: The Armada Job id
• ARMADA_QUEUE: Queue in which the job was submitted
• ARMADA_JOBSET_ID: JobSet id for which the job was submitted
• ARMADA_GANG_ID: Gang id in case it is gang job
• ARMADA_GANG_CARDINALITY: Number of jobs in the gang in case it is a gang job
• ARMADA_GANG_NODE_UNIFORMITY_LABEL_NAME: The node label name used for uniformity (e.g., "rack") in case it is a gang job
• ARMADA_GANG_NODE_UNIFORMITY_LABEL_VALUE: The actual value selected during scheduling (e.g., "rack-1") in case it is a gang job

If any envvar was already defined, Armada will not override it.

What this PR does / why we need it:

By injecting job info, Armada integrations like armada-spark could implement dynamic allocation where the initial set of driver + executors gets submitted as a non-preemptible gang, and the dynamic executors then use the gang info to leverage nodeSelectors to submit dynamic preemptible executors on the same set of nodes on which the initial gang is executing.

Which issue(s) this PR fixes:

Fixes #4455

Testing

1. armadactl create queue queue-a
2. armadactl submit example/example-job.yaml
3. kubectl describe <pod>
4. Validate it has ARMADA_JOB_ID, ARMADA_QUEUE, ARMADA_JOBSET_ID