Remove webfontloader and simplify web fonts

This patch removes the `webfontloader` JavaScript library in favor of
using `link` tags to load web font assets. `webfontloader` had its last
release in mid-2017, and we were using it in a very simple way.

This patch also makes the following related changes:

- Remove all font assets other than `woff`, which is widely supported:
  https://caniuse.com/woff
- Flatten font assets into `djangoproject/static/fonts/`
- Remove the `FiraMono-Medium` font variant assets since this variant
  was not being used
- Update outdated font-related references in the `styleguide.html`
  template

Author: adamzap

bower.json

@@ -3,7 +3,6 @@
   "private": true,
   "dependencies": {
     "jquery": "<2.0",
-    "webfontloader": "~1.5.10",
     "jquery-flot": "~0.8.3"
   }
 }

djangoproject/scss/_utils.scss

@@ -39,28 +39,22 @@ $red-dark: #6A0E0E;
 $red-dark-l10: lighten($red-dark, 10);
 $black: #0e1117;
 $black-light-5: lighten($black, 5);
-$font-path: "../fonts/fira-mono";
+$font-path: "../fonts";
 $logo-bg-dark: #272c27;
 
 
 // @font-face declarations
 
 @font-face {
     font-family: 'Fira Mono';
-    src: url('#{$font-path}/FiraMono-Regular.eot');
-    src: url('#{$font-path}/FiraMono-Regular.eot') format('embedded-opentype'),
-    url('#{$font-path}/FiraMono-Regular.woff') format('woff'),
-    url('#{$font-path}/FiraMono-Regular.ttf') format('truetype');
+    src: url('#{$font-path}/FiraMono-Regular.woff') format('woff');
     font-weight: 400;
     font-style: normal;
 }
 
 @font-face {
     font-family: 'Fira Mono';
-    src: url('#{$font-path}/FiraMono-Bold.eot');
-    src: url('#{$font-path}/FiraMono-Bold.eot') format('embedded-opentype'),
-    url('#{$font-path}/FiraMono-Bold.woff') format('woff'),
-    url('#{$font-path}/FiraMono-Bold.ttf') format('truetype');
+    src: url('#{$font-path}/FiraMono-Bold.woff') format('woff');
     font-weight: 700;
     font-style: normal;
 }

djangoproject/scss/font-awesome/_path.scss

@@ -3,12 +3,7 @@
 
 @font-face {
     font-family: 'FontAwesome';
-    src: url('#{$fa-font-path}/fontawesome-webfont.eot?v=#{$fa-version}');
-    src: url('#{$fa-font-path}/fontawesome-webfont.eot?#iefix&v=#{$fa-version}') format('embedded-opentype'),
-    url('#{$fa-font-path}/fontawesome-webfont.woff?v=#{$fa-version}') format('woff'),
-    url('#{$fa-font-path}/fontawesome-webfont.ttf?v=#{$fa-version}') format('truetype'),
-    url('#{$fa-font-path}/fontawesome-webfont.svg?v=#{$fa-version}#fontawesomeregular') format('svg');
-    //src: url('#{$fa-font-path}/FontAwesome.otf') format('opentype'); // used when developing fonts
+    src: url('#{$fa-font-path}/fontawesome-webfont.woff?v=#{$fa-version}') format('woff');
     font-weight: normal;
     font-style: normal;
 }