Update CSS font references

public/lib/adminlte/css/AdminLTE.css

@@ -29,6 +29,9 @@
  * Core: General Layout Style
  * -------------------------
  */
+
+@import url('../../../css/google-fonts.css');
+
 html,
 body {
   height: 100%;

public/lib/adminlte/css/AdminLTE.min.css

@@ -17,7 +17,7 @@
  * You should have received a copy of the GNU General Public License
  * along with Firefly III. If not, see <http://www.gnu.org/licenses/>.
  */
-
+@import url('../../../css/google-fonts.css');
 /*!
  *   AdminLTE v2.4.5
  *   Author: Almsaeed Studio