Bug 25166: Add "aria-hidden = true" to Font Awesome icons in the OPAC

Bug 25166: Add "aria-hidden = true" to Font Awesome icons in the OPAC

Font Awesome's accessibility guidelines
(https://fontawesome.com/v4.7.0/accessibility/) suggest that we include
'aria-hidden="true"' in the icon markup. This prevents screen
readers from trying to read the icon. This patch adds the attribute.

To test apply the patch and browse the OPAC looking for any problems
with icons: On search results, bibliographic details page, the cart,
lists, etc.

Check the source and verify that Font Awesome icons have the
"aria-hidden" attribute.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Attribute present, all looks good. The 'aria-label' attribute is
not translatable, but it's another problem.

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