Implement consistent admin interface

* Consistent route/model/controller/view layout
* Get rid of unused photos, speakers, dietchoices, social_events controllers
* Drop unused :public from Rooms and :description from CallForPapers

spec/factories/call_for_paper.rb

@@ -1,10 +1,8 @@
 # Read about factories at https://github.com/thoughtbot/factory_girl
 
 FactoryGirl.define do
-  factory :call_for_papers do
+  factory :call_for_paper do
     start_date { 1.day.ago }
     end_date { 7.days.from_now }
-    description 'We call for papers'
-    conference
   end
 end

spec/factories/photos.rb

@@ -1,14 +0,0 @@
-# Read about factories at https://github.com/thoughtbot/factory_girl
-include ActionDispatch::TestProcess
-
-FactoryGirl.define do
-  factory :photo do
-    picture { fixture_file_upload(Rails.root.join('app', 'assets', 'images', 'rails.png'), 'image/png') }
-    picture_file_name 'rails.png'
-    picture_content_type 'image/png'
-    picture_file_size '1024'
-    picture_updated_at { DateTime.now }
-    description 'Lorem Ipsum Dolor'
-    conference
-  end
-end