Hiera optimization: use a new hiera hook

Hiera optimization: use a new hiera hook

This patch optimizes how we deploy hiera by using a new
heat hook specifically designed to help compose hiera
within heat templates. As part of this change:

 - we update all the 'hiera' software configurations to set the group to hiera
   instead of os-apply-config.

 - The new format uses JSON instead of YAML. The hook actually writes
   out the hiera JSON directly so no conversion takes place. Arrays,
   Strings, Booleans all stay in their native formats. As such we can avoid
   having to do many of the awkward string and list conversions in t-h-t to
   support the previous YAML formatting.

 - The new hook prefers JSON over YAML so upgrading users will have the
   new files prefered. (we will post a cleanup routine for the old files
   soon but this isn't a new behavior, JSON is now simply prefered.)

 - A lot of services required edits to account for default settings that
   worked in YAML that no longer work correctly in the native JSON
   format. In almost all these cases I think the resulting codes looks
   cleaner and is more explicit with regards to what is getting
   configured in hiera on the actual nodes.

Depends-On: I6a383b1ad4ec29458569763bd3f56fd3f2bd726b
Closes-bug: #1596373

Change-Id: Ibe7e2044e200e2c947223286fdf4fd5bcf98c2e1