Fix various issues around OpenGraph representation of media (#14133)

- Fix audio attachments not being represented in OpenGraph tags
- Fix audio being represented as "1 image" in OpenGraph descriptions
- Fix video metadata being overwritten by paperclip-av-transcoder
- Fix embedded player not using Mastodon's UI
- Fix audio/video progress bars not moving smoothly
- Fix audio/video buffered bars not displaying correctly

app/javascript/styles/mastodon/basics.scss

@@ -68,7 +68,32 @@ body {
   }
 
   &.player {
-    text-align: center;
+    padding: 0;
+    margin: 0;
+    position: absolute;
+    width: 100%;
+    height: 100%;
+    overflow: hidden;
+
+    & > div {
+      height: 100%;
+    }
+
+    .video-player video {
+      width: 100%;
+      height: 100%;
+      max-height: 100vh;
+    }
+
+    .media-gallery {
+      margin-top: 0;
+      height: 100% !important;
+      border-radius: 0;
+    }
+
+    .media-gallery__item {
+      border-radius: 0;
+    }
   }
 
   &.embed {