Bug 23958: Use Font Awesome icon to replace "new window" icon image

Bug 23958: Use Font Awesome icon to replace "new window" icon image

This patch modifies several templates in order to eliminate the
dependency on an image file for styling certain links which open popups
or new windows. A Font Awesome icon is used instead.

To test, apply the patch and rebuild the staff client CSS
(https://wiki.koha-community.org/wiki/Working_with_SCSS_in_the_OPAC_and_staff_client).

Cataloging:

 - Create a new MARC record which has the same ISBN as a record in your
   catalog.
 - When you save the record it should warn you that it is a possible
   duplicate. The message should contain an icon-prefixed link to the
   existing record.
 - Clicking the link should open details about the title in a new
   window.

Circulation:

 - Enable the itemBarcodeFallbackSearch system preference.
 - Open a patron for checkout and enter a word in the "barcode" field
   instead of a barcode.
 - The page should return a list of titles to choose from. Each title
   should be a link with an icon. Clicking the link should open details
   about the title in a new window.

Acquisitions:

 - Go to Acquistisions -> Vendor -> Basket.
 - Choose "Add to basket" -> From an external source.
 - Search for and select a record which exists in your catalog.
 - You should be taken to a page with a "Duplicate warning" message. The
   message should contain an icon-prefixed link to the existing record.
 - Clicking this link should open details about the title in a new
   window.

 - Create a MARC file with two records: One which exists in your catalog
   and one which doesn't. Stage that file for import.
 - Choose "Add to basket" again and select "From a staged file."
 - Select the file you staged.
 - You should be taken to a page with a "Duplicate warning" message. The
   message should contain an icon-prefixed link to the existing record.
 - Clicking the link should open details about the title in a new
   window.

Patrons:

 - Create a new patron which has the same name and birthday as an
   existing patron.
 - When you save the record you should be shown a duplicate warning. The
   link to the possible duplicate patron should be prefixed with an icon
   and should open the patron's details in a popup window.

Signed-off-by: Maryse Simard <maryse.simard@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>