Feature: switch visibility with `update_repo_settings`

[Wauplin]

Follow-up PR after #2502.

Now that we have a generic update_repo_settings, we can add the option to switch visibility status of a repo. This would be a drop-in replacement for update_repo_visibility:

- update_repo_visibility(repo_id, private=True)
+ update_repo_settings(repo_id, private=True)

TODO:

• add a private attribute to update_repo_settings
• make both gated and private attributes optional (default to None)
• check update_repo_settings inputs => either gated is passed, or private, or both. If both gated and private are None, raise a ValueError.
• add gated and private to the request payload only if not None
• update update_repo_settings docstring
• update all references of update_repo_visibility in docs
• add @_deprecate_method decorator to update_repo_visibility (will be removed in 0.29.x)

[WizKnight]

Hey @Wauplin :), I'd be happy to take on this PR!😊

[Wauplin]

Closed by #2502 and #2541 from @WizKnight !