[Helm] Add option to specify job label for ServiceMonitor

[hamza3202]

What this PR does / why we need it:

This PR adds an option to specify spec.jobLabel field for ServiceMonitor. Which can be used to configure prometheus job name based on the value of a label on the service. Using a label on the service as the job name helps organising the jobs and preventing clashes.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

How Has This Been Tested?

• Ran helm template with default values, spec.jobLabel is not set in the generated yaml. (controller.metrics.enabled and controller.metrics.serviceMonitor.enabled were set to true to enable generation of ServiceMonitor)
• Ran helm template with custom value for controller.metrics.serviceMonitor.jobLabel, A new field was added in ServiceMonitor with the correct value.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added tests to cover my changes.
• All new and existing tests passed.

[k8s-ci-robot]

Hi @hamza3202. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[hamza3202]

/assign @ChiefAlexander

[hamza3202]

/assign @cmluciano

[hamza3202]

I have created this PR because I mistakenly closed the original PR.

[hamza3202]

@ChiefAlexander can you review/merge this PR ASAP? I have had to do rebase a couple of times already.

[ChiefAlexander]

/ok-to-test

[ChiefAlexander]

/lgtm

[ChiefAlexander]

Thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ChiefAlexander, hamza3202

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