Add azure backup capabilities

[Taliik]

Summary of changes

Checklist

• [ ] Link to issue this PR refers to: https://github.com/crate/cloud/issues/1368
• [ ] Relevant changes are reflected in CHANGES.rst
• [ ] Added or changed code is covered by tests
• [ ] Documentation has been updated if necessary
• [ ] Changed code does not contain any breaking changes (or this is a major version change)

[tomach]

Probably also in the operator we would need to add the new backup location type somehow to the restoreSnapshot CRD and consider it when creating the repo for restoring a snapshot? https://github.com/crate/crate-operator/blob/f/add-azure-backup/crate/operator/restore_backup.py#L694