[8.x](backport #2625) [Asset Inventory][Azure] Add Acitive Directory fetcher to fetch Service Principals

[mergify]

Summary of your changes

This PR adds an Active Directory fetcher and fetchers Azure Service Principals. It utilizes microsoftgraph/msgraph-sdk-go, since this Active Directory API is not exposed in the SDK we've been using so far. This is the recommended approach.

Screenshot/Data

Related Issues

Closes https://github.com/elastic/security-team/issues/10161

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have added the necessary README/documentation (if appropriate)

---

This is an automatic backport of pull request #2625 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of d849030 has failed:

On branch mergify/bp/8.x/pr-2625
Your branch is up to date with 'origin/8.x'.

You are currently cherry-picking commit d8490308.
  (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:   go.mod
	modified:   internal/flavors/assetinventory/strategy.go
	new file:   internal/flavors/assetinventory/strategy_test.go
	modified:   internal/inventory/ASSETS.md
	modified:   internal/inventory/asset.go
	modified:   internal/inventory/azurefetcher/azurefetchers.go
	new file:   internal/inventory/azurefetcher/fetcher_activedirectory.go
	new file:   internal/inventory/azurefetcher/fetcher_activedirectory_test.go
	new file:   internal/inventory/azurefetcher/mock_activedirectory_provider.go
	new file:   internal/resources/providers/msgraph/mock_provider_api.go
	new file:   internal/resources/providers/msgraph/provider.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   go.sum

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

[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.x/pr-2625 upstream/mergify/bp/8.x/pr-2625
git merge upstream/8.x
git push upstream mergify/bp/8.x/pr-2625