[ResponseOps] New metricsets for Kibana stack monitoring

[chrisronline]

Relates to elastic/kibana#123416
Relates to elastic/kibana#123637

This PR introduces an additional metric sets for Kibana stack monitoring related to a new endpoints added for better observability into Kibana alerting.

[mergify]

This pull request does not have a backport label. Could you fix it @chrisronline? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 7./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[elasticmachine]

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• Start Time: 2022-05-24T18:29:44.531+0000

• Duration: 55 min 10 sec

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Test	Results
Failed	0
Passed	3539
Skipped	870
Total	4409

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[sayden]

It's almost there, I just left some comments of files that have been removed without need. I need to check yet the dependencies added to the project, probably they aren't necessary either.

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b rops/monitoring_collection upstream/rops/monitoring_collection
git merge upstream/master
git push upstream rops/monitoring_collection

[neptunian]

Do we need to update https://github.com/elastic/beats/blob/main/metricbeat/module/kibana/_meta/fields.yml?

[chrisronline]

@neptunian I honestly don't know. Happy to update if it's necessary

[chrisronline]

@fearful-symmetry Okay I fixed up a bit and think it's ready for another pass!

[fearful-symmetry]

Aside from linter errors, mostly looking good, just a few small things.

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b rops/monitoring_collection upstream/rops/monitoring_collection
git merge upstream/main
git push upstream rops/monitoring_collection

[chrisronline]

@fearful-symmetry CI is green! I think all the linting issues are sorted out

[fearful-symmetry]

Not familiar with the Kibana APIs, but code LGTM.

[chrisronline]

@fearful-symmetry Can you merge this for me? I don't know why I don't have access

[chrisronline]

@fearful-symmetry Thank you!