Bug 16792: Add Font Awesome Icon and mini button to Keyword to MARC mapping section

Bug 16792: Add Font Awesome Icon and mini button to Keyword to MARC mapping section

Improve Admin > Keyword to MARC mapping to fit with others interfaces in Koha.
This bug change "Delete" link with a mini-button and introduce the trash icon.

To test:
-Apply patch
-Goto Admin > Keyword to MARC mapping
-Select one framework
-Add some mappings
-Notice about the new button with trash icon

Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>