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/stream_entry_finder.rb

@@ -1,34 +0,0 @@
-# frozen_string_literal: true
-
-class StreamEntryFinder
-  attr_reader :url
-
-  def initialize(url)
-    @url = url
-  end
-
-  def stream_entry
-    verify_action!
-
-    case recognized_params[:controller]
-    when 'stream_entries'
-      StreamEntry.find(recognized_params[:id])
-    when 'statuses'
-      Status.find(recognized_params[:id]).stream_entry
-    else
-      raise ActiveRecord::RecordNotFound
-    end
-  end
-
-  private
-
-  def recognized_params
-    Rails.application.routes.recognize_path(url)
-  end
-
-  def verify_action!
-    unless recognized_params[:action] == 'show'
-      raise ActiveRecord::RecordNotFound
-    end
-  end
-end