multihost: add MultihostBackupHost and BackupTopologyController

[pbrezina]

MultihostBackupHost: This is a base host that provides automatic host backup and restore functionality.

BackupTopologyController: This controller provides automatic backup and restore of the topology hosts.

[justin-stephenson]

With these changes should I remove these lines from SSSD/sssd-test-framework#119 ?

+        # Backup so we can restore to this state after each test
+        self.backup_data[ipa] = ipa.backup()
+        self.backup_data[trusted] = trusted.backup()
+        self.backup_data[client] = client.backup()

Or any other changes needed?

[pbrezina]

There's SSSD/sssd-test-framework#121 (please, review it as well) that makes use of it, this is the change https://github.com/SSSD/sssd-test-framework/pull/121/files#diff-caf41b02ccb1ea1302c38f054d2709dd258847bb3228a04734a956c0ec49fab2L138-R93.

You either leave the code as is (which is perfectly fine), or remove it and call super().topology_setup() to do the backup for you. It's either or.

[justin-stephenson]

Ack, thank you.