MDBCI now supports separate Galera server .cnf configuring.
Changing MDBCI config template in order to use this MDBCI
capability. It allows to use any MariaDB product in the
backend (Community or Enterprise, production, staging or CI)
This fixes the problem where an encrypted connection would not be created
even though the option for it was there. Also made it configurable outside
of the constructor to make it easier to use in tests.
