Implements backup, etcd-backup and restore hooks.
Operations can fail so there is a second parameter,
'success' that is used to notify applications if an operation
failed.
Restore hooks are in place but not used by ansible playbooks.
Separate semantic check action.
Revert backup operations by keeping a list of all pre- operations
with their associated 'revert' action and also, keeping in mind
the logical order of the pre-backup and pre-etcd backup operations.
Story: 2007960
Task: 40769
Signed-off-by: Andrei Grosu <andrei.grosu@windriver.com>
Change-Id: I0ebab45f4846cbcd25fecac6bf99195d9047eb8a
0e1bf35613