Add font-face for FontAwesome to font.less (and admin.css and ipsilon.css)
    
    The admin template navbar drop-down uses FontAwesome for the down-arrow
    glyph, but there's no font-face statement in the page CSS to define and
    load FA.  Fix that by adding a statement pointing to a system copy of the
    font.
    
    Add a Requires: for the system font.
    
    Merges: #93
    Signed-off-by: Howard Johnson <merlin@merlinthp.org>
    Reviewed-by: Patrick Uiterwijk <puiterwijk@redhat.com>