Add plyr as main player

Also plyr supports switch quality

youtube/static/js/plyr-start.js

@@ -0,0 +1,23 @@
+// @license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3-or-Later
+const player = new Plyr(document.getElementById('js-video-player'), {
+    disableContextMenu: false,
+    captions: {
+        active: true,
+        language: 'en'
+    },
+    controls: [
+        'play-large',
+        'play',
+        'progress',
+        'current-time',
+        'mute',
+        'volume',
+        'captions',
+        'settings',
+        'fullscreen'
+    ],
+    iconUrl: "/youtube.com/static/modules/plyr/plyr.svg",
+    blankVideo: "/youtube.com/static/modules/plyr/blank.webm",
+    debug: false
+});
+// @license-end

youtube/static/watch.css

@@ -30,6 +30,20 @@ video {
     max-height: 480px;
 }
 
+/* plyr fix */
+.plyr:-moz-full-screen video {
+    max-height: initial;
+}
+.plyr:-webkit-full-screen video {
+    max-height: initial;
+}
+.plyr:-ms-fullscreen video {
+    max-height: initial;
+}
+.plyr:fullscreen video {
+    max-height: initial;
+}
+
 a:link {
     color: var(--link);
 }