Replace best_in_place editor on admin settings page (#2789)

* Remove best_in_place

* Replace best_in_place usage with rails helpers

* Move admin/settings#index to #edit action

* Remove click_to__edit from i18n

config/routes.rb

@@ -76,7 +76,7 @@ Rails.application.routes.draw do
   namespace :admin do
     resources :pubsubhubbub, only: [:index]
     resources :domain_blocks, only: [:index, :new, :create, :show, :destroy]
-    resources :settings, only: [:index, :update]
+    resource :settings, only: [:edit, :update]
     resources :instances, only: [:index]
 
     resources :reports, only: [:index, :show, :update] do