When 'cinder_galera_use_ssl' is True, use an encrypted connection to
the database using either a self-signed or user-provided CA certificate.
A new non-voting test has been added to verify that the role remains
functional when enabling SSL features.
Partial-Bug: 1667789
Change-Id: Ifeda0acb4b70ba313e6572c806125d31ab3eb300
Depends-On: I95cc994df5118fce7ce588fc0bff979bc283a6f3