Update status embeds (#4742)

- Use statuses controller for embeds instead of stream entries controller
- Prefer /@:username/:id/embed URL for embeds
- Use /@:username as author_url in OEmbed
- Add follow link to embeds which opens web intent in new window
- Use redis cache in development
- Cache entire embed

app/lib/status_finder.rb

@@ -1,20 +1,20 @@
 # frozen_string_literal: true
 
-class StreamEntryFinder
+class StatusFinder
   attr_reader :url
 
   def initialize(url)
     @url = url
   end
 
-  def stream_entry
+  def status
     verify_action!
 
     case recognized_params[:controller]
     when 'stream_entries'
-      StreamEntry.find(recognized_params[:id])
+      StreamEntry.find(recognized_params[:id]).status
     when 'statuses'
-      Status.find(recognized_params[:id]).stream_entry
+      Status.find(recognized_params[:id])
     else
       raise ActiveRecord::RecordNotFound
     end