[Feature][metrics] ray_job_execution_duration_seconds

[win5923]

Description

To improve observability in KubeRay, we propose adding a new metric, ray_job_execution_duration_seconds. This metric will track the execution duration of RayJob resources from creation to completion or failure, helping users analyze job performance and optimize processing time.

Proposed Metric

Metric Name	Type	Description	Labels
ray_job_execution_duration_seconds	Histogram	The time between RayJob CRs created to completed/Failed.	- result: Complete/Failed - namespace

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[kevin85421]

It will be helpful for users to know the time for different stages of RayJob lifecycle, e.g. cluster creation, submitter creation, ... etc.

[troychiu]

cc @kevin85421 could you assign this to me? Thank you.

[kevin85421]

Closed by #3488