Add default site customization pages

From now on these static pages:

`/privacy'
`/conditions'
`/accesibility'
`/help/faq'
`/welcome'

have been moved to the DB and can be modified easily by any
administrator in `/admin/site_customization/pages'

spec/controllers/pages_controller_spec.rb

@@ -32,7 +32,7 @@ describe PagesController do
     end
 
     it "includes a faq page" do
-      get :show, id: "help/faq/index"
+      get :show, id: :faq
       expect(response).to be_ok
     end
   end