[8.15](backport #40683) Add support of snapshot in vSphere virtualmachine metricset

[mergify]

Add support of adding snapshot details to the Virtualmachine object in Vsphere.
It caters to the snapshot and any childsnapshots as well.

Relates: https://github.com/elastic/obs-integration-team/issues/34

---

This is an automatic backport of pull request #40683 done by Mergify.

[mergify]

Cherry-pick of 7f29f60 has failed:

On branch mergify/bp/8.15/pr-40683
Your branch is up to date with 'origin/8.15'.

You are currently cherry-picking commit 7f29f6021b.
  (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

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   metricbeat/docs/fields.asciidoc
	both modified:   metricbeat/module/vsphere/fields.go
	both modified:   metricbeat/module/vsphere/virtualmachine/_meta/data.json
	both modified:   metricbeat/module/vsphere/virtualmachine/_meta/fields.yml
	deleted by us:   metricbeat/module/vsphere/virtualmachine/data.go
	deleted by us:   metricbeat/module/vsphere/virtualmachine/data_test.go
	both modified:   metricbeat/module/vsphere/virtualmachine/virtualmachine.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.

[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-40683 upstream/mergify/bp/8.15/pr-40683
git merge upstream/8.15
git push upstream mergify/bp/8.15/pr-40683

[ishleenk17]

Closing in lieu of #40830