Bug 16023 - Use Font Awesome icons on audio alerts page

Bug 16023 - Use Font Awesome icons on audio alerts page

The audio alerts management page uses Glyphicons in a few places. This
patch replaces them with Font Awesome icons.

To test, apply the patch for Bug 15886 if necessary and enable
the AudioAlerts system preference.

 - Go to Administration -> Audio alerts
 - Confirm that icons for "Edit" and "Delete selected" look correct.
 - Edit an existing alert and confirm that the "play" button looks
   correct and works correctly.

Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com
(cherry picked from commit 5d266693edc042c0a2f795588058ae8b3d12da22)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>