Today we have multiple ways to define settings when a user needs to create a repository:
* in `elasticsearch.yml` file using `repositories.azure` prefix
* when creating the repository itself with `PUT _snaphot/repo`
The plan is to:
* Deprecate `repositories.azure` settings in 5.x (done with #22856)
* Remove in 6.x (this PR)
Related to #22800
This change removes the ability to set region for s3 repositories.
Endpoint should be used instead if a custom s3 location needs to be
used.
closes#22758
Follow up of #22857 where we deprecate automatic creation of azure containers.
BTW I found that the `AzureSnapshotRestoreServiceIntegTests` does not bring any value because it runs basically a Snapshot/Restore operation on local files which we already test in core.
So instead of trying to fix it to make it pass with this PR, I simply removed it.
