Set reasonable TTL defaults for Ceilometer DB
Set reasonable TTL defaults for Ceilometer DB

By deafult, we let the data live for ever. Which isnt very efficient.
Lets expose params to tweak this and use a reasonable default.

Change-Id: I145fa73a7af9cb4135ba910d3659853b3baa893d

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