Change public statuses pages to mount the web UI (#19301)

app/controllers/home_controller.rb

@@ -1,13 +1,12 @@
 # frozen_string_literal: true
 
 class HomeController < ApplicationController
+  include WebAppControllerConcern
+
   before_action :redirect_unauthenticated_to_permalinks!
-  before_action :set_referrer_policy_header
   before_action :set_instance_presenter
 
-  def index
-    @body_classes = 'app-body'
-  end
+  def index; end
 
   private
 
@@ -19,10 +18,6 @@ class HomeController < ApplicationController
     redirect_to(redirect_path) if redirect_path.present?
   end
 
-  def set_referrer_policy_header
-    response.headers['Referrer-Policy'] = 'origin'
-  end
-
   def set_instance_presenter
     @instance_presenter = InstancePresenter.new
   end