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)

[plaharanne]

👍

[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