Add autoplay functionality in Plyr video player

Introduce autoplay feature in the Plyr video player based on the configuration settings.

youtube/static/js/plyr-start.js

@@ -14,6 +14,9 @@
       captionsActive = false;
   }
 
+  // AutoPlay
+  let autoplayActive = data.settings.autoplay_videos === true ? true : false;
+
   let qualityOptions = [];
   let qualityDefault;
   for (let src of data['uni_sources']) {
@@ -72,6 +75,7 @@
   });
 
   const player = new Plyr(document.getElementById('js-video-player'), {
+    autoplay: autoplayActive,
     disableContextMenu: false,
     captions: {
       active: captionsActive,