Map Mysql to isolated networks

This change adds parameters to specify which networks the MySQL
service will use. If the internal_api network exists the MySQL
service will bind to the IP address on that network, otherwise
the services will default to the IP on the Undercloud 'ctlplane'
network.

This patch also drop the old 'controller_host' variable from
the puppet controller template since it is no longer in use.

Change-Id: I4fba2c957f7db47e916bc269fb4bd32ccc99bd4c