When 'glance_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: I18e9d47e88e61ff287e5120dead49b02cdf1f8ac
Depends-On: I95cc994df5118fce7ce588fc0bff979bc283a6f3