Documentation: add Azure workload identity example

[GVengelen]

What this PR does

I've added an configuration example for using workload identity on Azure object storage for Mimir.

Which issue(s) this PR fixes or relates to

No issue

Checklist

• [N/A] Tests updated.
• Documentation added.
• [x ] CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• about-versioning.md updated with experimental features.

[CLAassistant]

All committers have signed the CLA.

[dimitarvdimitrov]

this is great! Thank you for the contribution! I'll leave someone from the docs team to vet this for style and structure, but the content makes sense (even though I'm not an azure expert)

[dimitarvdimitrov]

The CHANGELOG has just been cut to prepare for the next Mimir release. Please rebase main and eventually move the CHANGELOG entry added / updated in this PR to the top of the CHANGELOG document. Thanks!

[GVengelen]

The CHANGELOG has just been cut to prepare for the next Mimir release. Please rebase main and eventually move the CHANGELOG entry added / updated in this PR to the top of the CHANGELOG document. Thanks!

@tacole02 Can you have a second look, I think I've processed all the comments

[tacole02]

Looks great. Thank you!

[dimitarvdimitrov]

a few nitpicks on the changelog

[github-actions]

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