docs: Adding a private OCI registry section

[GuillaumeASSIER]

Changes made:

I create a private registry section to explain where to add auth.json file for OCI auth

[gemini-code-assist]

Code Review

This pull request adds a new section to the documentation about using private OCI registries. The change is a good addition, explaining where to place the auth.json file for authentication. I have one suggestion to improve the clarity of the explanation to avoid potential confusion for users.

[GuillaumeASSIER]

Hi @cgwalters 👋,
Why did you remove the documentation label ?

[cgwalters]

Thanks! We have this in a few places in the docs, but having a copy here is a good idea too!

I think at some point soon I may try to add a proper man page for the auth file instead and have the docs reference it.

[cgwalters]

Why did you remove the documentation label ?

I replaced it with a different area/documentation label globally instead (not just on this PR).

Thanks for your contribution!