[DOCS] config example for AD domain credential for MSSQL module

[geekpete]

Provide an example of using credentials with a domain for the MSSQL Metricbeat module.
Potentially addresses #13006 and #12267
Backport to 7.x minor version branches

[geekpete]

Forgot make update again, got that done now after some wrangling with python and go versions in my environment.

[dedemorton]

@geekpete are you sure you ran make update? After pulling down this PR and running make update, I see that a couple files are changed:

On branch pr_13594
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   x-pack/metricbeat/metricbeat.reference.yml
	modified:   x-pack/metricbeat/modules.d/mssql.yml.disabled

[dedemorton]

Unrelated to CI error, but you probably want a [float] tag here before this section (otherwise this content will become a new topic).

[dedemorton]

jenkins test this again

[exekias]

@sayden any opinions on this change?

[dedemorton]

@geekpete I think the problem here is that your branch contains an old file that has invalid asciidoctor:

07:40:29 INFO:build_docs:asciidoctor: ERROR: ../../libbeat/docs/shared-ssl-config.asciidoc: line 9: malformed preprocessor directive - text not permitted: endif::["{beatname_lc}"!="apm-server"]

I don't see this problem in the master, so rebasing should fix it.

[dedemorton]

@geekpete I hope you don't mind, but I went ahead and rebased this for you. Figured you'd want o move this forward. It should fix the CI so you can move this forward.

[dedemorton]

@sayden @exekias I've pushed some changes that should fix the docs CI. Can someone give this a technical review so we can get it merged? I feel badly that it's been open for so long.

[exekias]

Thank you @dedemorton !

[geekpete]

Thanks for the work on getting this one finished, Team!

Does this also mean we can close the related bug issues?

• [Metricbeat] MSSQL module cannot parse username if domain is included within the host string #13364
• [Metricbeat][MSSQL] Docs clarifications for credentials and permissions #13006
• [Metricbeat] Update MSSQL docs #12267

UPDATE: #12267 seems more related to a separate issue #14585 maybe we can also make it clear in the docs in a separate PR that this functionality isn't yet implemented.