fix custom font call for Firefox display

gargantext-org-website/css/fonts.scss

+@font-face {
+    font-family: 'garg-icons';
+    src: url('fonts/garg-icons.eot?9cya6v') format('embedded-opentype'),
+            url('fonts/garg-icons.woff?9cya6v') format('woff'),
+            url('fonts/garg-icons.ttf?9cya6v') format('truetype'),
+            url('fonts/garg-icons.svg?9cya6v#garg-icons') format('svg');
+    font-weight: normal;
+    font-style: normal;
+    font-display: block;
+}

gargantext-org-website/css/style-garg-icons.sass

-@font-face
-  font-family: 'garg-icons'
-  src: url('fonts/garg-icons.eot?9cya6v')
-  src: url('fonts/garg-icons.eot?9cya6v#iefix') format('embedded-opentype')
-  src: url('fonts/garg-icons.ttf?9cya6v') format('truetype')
-  src: url('fonts/garg-icons.woff?9cya6v') format('woff')
-  src: url('fonts/garg-icons.svg?9cya6v#garg-icons') format('svg')
-  font-weight: normal
-  font-style: normal
-  font-display: block
+// include fonts from a SCSS format (the font files calls in sass syntax don't work)
+@import 'fonts'
 
 [class^="icon-"], [class*=" icon-"]
   /* use !important to prevent issues with browser extensions that change fonts */