Bug 16005 - Standardize use of icons for delete and cancel operations

Bug 16005 - Standardize use of icons for delete and cancel operations

This patch makes changes to Font Awesome icons in order to make icon
choice consistent for common actions.

<i class="fa fa-trash"></i> where something is deleted, removed, or
emptied.

<i class="fa fa-remove"></i> where an operation is cancelled (also where
selections are cancelled, as in checkboxes).

<i class="fa fa-times-circle"></i> for "close," as in baskets and
windows.

To test, apply the patch and view the following pages to confirm that
the correct icon is used:

- Acquisitions -> Vendor -> Vendor delete button.
- Acquisitions -> Vendor -> Edit -> Delete contact button.
- Acquisitions -> Invoices ->  Delete menu item.
- Cataloging -> Edit record -> Authority search pop-up (triggered from
  the tag editor for a tag linked to an authority) -> Clear field button
- Authorities -> Authority detail -> Delete button.
- Tools -> Quotes editor -> Quotes delete button.
- Reports -> View saved report -> Delete button.
- Reports -> Saved reports -> Delete menu item.
- Serials -> Subscription details -> Subscription close button.
- Administration -> Budgets -> Delete menu item.
- Administration -> Item search fields -> Delete button.
- Administration -> Z39.50/SRU servers -> Delete menu item.
- Catalog -> Advanced search -> Clear fields link.
- Cataloging -> Advanced editor -> Macros -> Delete macro button.
- Circulation -> Checkout -> Check out an item which is on hold for
  another patron. "Cancel checkout and place hold" button now uses the
  icon used elsewhere for holds.
- Course reserves -> Course -> Delete course button.
- Patrons -> Patron lists -> Add patrons -> Remove selected button.
- Acquisitions -> Suggestions -> Suggestion details -> Delete button.
- Lists -> List contents -> Remove selected button.

Followed test plan, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>