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

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class StatusFinder
+  attr_reader :url
+
+  def initialize(url)
+    @url = url
+  end
+
+  def status
+    verify_action!
+
+    case recognized_params[:controller]
+    when 'stream_entries'
+      StreamEntry.find(recognized_params[:id]).status
+    when 'statuses'
+      Status.find(recognized_params[:id])
+    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