add font resources and update head for local font usage

Author: jannikmenzel

assets/css/main.css

@@ -44,4 +44,18 @@ body {
 .no-style {
     all: unset;
     display: contents;
-}
+}
+
+.material-icons {
+    font-family: 'Material Icons', serif;
+    font-weight: normal;
+    font-style: normal;
+    font-size: 24px;
+    display: inline-flex;
+    line-height: 1;
+    text-transform: none;
+    letter-spacing: normal;
+    word-wrap: normal;
+    white-space: nowrap;
+    direction: ltr;
+}