Add tabnav, dedicated auths view to RS service page

Includes a nicer view and illustration for when no auths exist yet

config/routes.rb

@@ -48,7 +48,8 @@ Rails.application.routes.draw do
     end
 
     resource :storage, controller: 'remotestorage', only: [:show] do
-      resources :rs_auths, only: [:destroy] do
+      get :apps, to: "rs_auths#index"
+      resources :rs_auths, only: [:index, :destroy] do
         member do
           get :revoke, to: 'rs_auths#destroy'
           get :launch_app