[8.x](backport #4398) profiling: add documentation for the config file and CLI arguments

[mergify]

Description

Extend the documentation about the format of the config file and the CLI arguments.

Documentation sets edited in this PR

Check all that apply.

• Stateful (docs/en/observability/*)
• Serverless (docs/en/serverless/*)
• Integrations Developer Guide (docs/en/integrations/*)
• None of the above

---

This is an automatic backport of pull request #4398 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e335f27 has failed:

On branch mergify/bp/8.x/pr-4398
Your branch is up to date with 'origin/8.x'.

You are currently cherry-picking commit e335f277.
  (fix conflicts and run "git cherry-pick --continue")
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  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   docs/en/observability/profiling-advanced-configuration.asciidoc
	new file:   docs/en/observability/profiling-config-file.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   docs/en/observability/index.asciidoc
	deleted by us:   docs/en/observability/profiling-envs.asciidoc

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

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