[8.15](backport #40441) [vSphere][datastore] Add additional metrics

[mergify]

Description

Added following new metrics for the datastore metricset in the vSphere metricbeat module. added new performance API to get more detailed info from the vSphere.

Metrics Type	Metrics	Field Mappings
Datastore performance
	datastore.read.average (KBps)	datastore.read.bytes
	datastore.write.average (KBps)	datastore.write.bytes
	datastore.datastoreIops.average (num)	datastore.iops
	datastore.totalReadLatency.average (ms)	datastore.read.latency.total.ms
	datastore.totalWriteLatency.average (ms)	datastore.write.latency.total.ms
Datastore Summry
	Datastore.OverallStatus	datastore.status
	Datastore.Host	datastore.host.count
	Datastore.Host	datastore.host.names
	Datastore.Vm	datastore.vm.count
	Datastore.Vm	datastore.vm.names

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Related issues

• Relates https://github.com/elastic/obs-integration-team/issues/19

---

This is an automatic backport of pull request #40441 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 94ca509 has failed:

On branch mergify/bp/8.15/pr-40441
Your branch is up to date with 'origin/8.15'.

You are currently cherry-picking commit 94ca5096f8.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   CHANGELOG.next.asciidoc
	modified:   metricbeat/docs/fields.asciidoc
	modified:   metricbeat/module/vsphere/datastore/_meta/data.json
	modified:   metricbeat/module/vsphere/datastore/_meta/fields.yml
	new file:   metricbeat/module/vsphere/datastore/data.go
	new file:   metricbeat/module/vsphere/datastore/data_test.go
	modified:   metricbeat/module/vsphere/datastore/datastore.go
	modified:   metricbeat/module/vsphere/datastore/datastore_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   metricbeat/module/vsphere/fields.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[botelastic]

This pull request doesn't have a Team:<team> label.

[ishleenk17]

/test

[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 mergify/bp/8.15/pr-40441 upstream/mergify/bp/8.15/pr-40441
git merge upstream/8.15
git push upstream mergify/bp/8.15/pr-40441

[lalit-satapathy]

LGTM backport PR.