Re-enable manila dashboard
Re-enable manila dashboard

The Shared File Systems service (manila) provides
a dashboard plugin that needs to be enabled by
tripleo. It appears that it was disabled inadvertently
while triaging a bug with the dashboard and sqlite.

See: Launchpad bug #1766184
and associated commit: https://review.opendev.org/#/c/613186/

Change-Id: If4bc4ed0e9fa31e11a5a701dc57ffdf67aade861
Closes-Bug: #1832302

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates