Clean up and improve generated OpenGraph tags (#4901)

- Return all images as og:image
- Return videos as og:image (preview) and og:video
- Return profile:username on profiles

app/serializers/oembed_serializer.rb

@@ -45,7 +45,7 @@ class OEmbedSerializer < ActiveModel::Serializer
       height: height,
     }
 
-    content_tag(:iframe, nil, attributes) + content_tag(:script, nil, src: full_asset_url('embed.js'), async: true)
+    content_tag(:iframe, nil, attributes) + content_tag(:script, nil, src: full_asset_url('embed.js', skip_pipeline: true), async: true)
   end
 
   def width