This commit changes how fonts are used.
- remove usage of bundled fonts and only system fonts are used instead
- by using alias in httpd conf
- by using local("Font Name") directive in font-face
- removed usage of overpass font
- redefined Open Sans font-face declarations. Note: upstream is doing the
same change so we will be fine on upgrade.
- introduce variable.less for variable definitions and overrides. This file
will be very useful when we upgrade to newer RCUE so we will be able to
redefine their and bootstrap's variables.
Fixes: https://fedorahosted.org/freeipa/ticket/2861
