Bug 1316917: New approach to star rating using bootstrap glyphs

This is a slimmer / stripped down system for doing jquery ratings.

Instead of relying on styling radio buttons it relies on bootstrap
glyphs and a hidden input field.

The code is also controlled by a pieform element

See lib/form/elements/ratings.php for more info about that part

It also has some new settings in the Extensions -> artefact -> comment
config form. They include settign the colour for the star icon, or
using a different icon, eg hearts/thumbs up, and the number of ratings
to show (3 - 12)

behatnotneeded

Change-Id: Ibf529efcb9a665c9f303242ed12d0c7b3dee2356
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit d1bf622a)