add arimo font family (#86020)

README

@@ -451,6 +451,13 @@ copyright notices:
   #
   # https://www.fontsquirrel.com/license/nunito-sans
 
+* Arimo
+  # Copyright (c) 2013 Steve Matteson.
+  #
+  # This Font Software is licensed under the Apache License Version 2.0.
+  #
+  # https://www.fontsquirrel.com/license/arimo
+
 ~~~~
 
 Some theme variant files have their own specific licenses; refer to

static/includes/fonts/_arimo.scss

@@ -0,0 +1,20 @@
+$arimo-font-path: '/static/fonts/Arimo' !default;
+
+@mixin arimo-font($type, $weight, $style: normal) {
+    @font-face {
+        font-family: 'Arimo';
+        src: url('#{$arimo-font-path}/Arimo-#{$type}.woff2') format('woff2');
+        font-weight: $weight;
+        font-style: $style;
+    }
+}
+
+@mixin arimo-font-pair($type, $weight) {
+       @include arimo-font($type, $weight);
+       @include arimo-font(#{$type}Italic, $weight, italic);
+}
+
+@include arimo-font-pair('Regular', 400);
+@include arimo-font-pair('Medium', 500);
+@include arimo-font-pair('SemiBold', 600);
+@include arimo-font-pair('Bold', 700);