Add commands for database backup and recovery

Uses the support [1] for database backups added to Kolla Ansible in the
Stein release.

Adds the following new commands:

kayobe overcloud database backup [--incremental]
kayobe overcloud database recover [--force-recovery-host <host>]

The recovery command is for recovering a clustered database that has
lost quorum.

[1] https://docs.openstack.org/kolla-ansible/latest/admin/mariadb-backup-and-restore.html

Change-Id: Ie16354cd01ea7dd83cd3d4058dd8451b8387600b
Story: 2005015
Task: 29493