helm: Add metrics port exposure via service and Prometheus ServiceMonitors

[jwitko]

Fixes #13990.

Description

This PR provides a way to easy way to expose a configured metrics port via the existing services and also optionally generate ServiceMonitor resources for users leveraging Prometheus.

Release note

Add metrics port exposure via services and optional Prometheus ServiceMonitors to helm chart

This PR has:

• been self-reviewed.
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[abhishekagarwal87]

I will take a look soon.

[github-actions]

This pull request has been marked as stale due to 60 days of inactivity.
It will be closed in 4 weeks if no further activity occurs. If you think
that's incorrect or this pull request should instead be reviewed, please simply
write any comment. Even if closed, you can still revive the PR at any time or
discuss it on the dev@druid.apache.org list.
Thank you for your contributions.

[hfinucane]

This would still be a good idea.

[asdf2014]

@jwitko Thanks for your contribution. As mentioned in PR #15904, we have migrated the Helm Chart to a new repository, you are welcome to raise up new PR there and we can maintain the Druid Helm Chart together in new repository. And this PR will closed soon. Thank you again for your understanding and collaboration.

[github-actions]

This pull request has been marked as stale due to 60 days of inactivity.
It will be closed in 4 weeks if no further activity occurs. If you think
that's incorrect or this pull request should instead be reviewed, please simply
write any comment. Even if closed, you can still revive the PR at any time or
discuss it on the dev@druid.apache.org list.
Thank you for your contributions.

[github-actions]

This pull request/issue has been closed due to lack of activity. If you think that
is incorrect, or the pull request requires review, you can revive the PR at any time.