Build dummy app successfully on api and frontend

  * Move ransack to common spree dependencies for now as we're depending
    on a rails4 branch and all spree components require it
  * Remove deface dependency
  * Rails dependency is redundant since spree_core already requires it
  * HTTP method should explictly set in routes `match`
Update action_controller `process` method signature

As of Rails 4 we should pass the HTTP method as second argument
Remove `caches_page` from Spree::ContentController

That method has been removed from Rails 4 and put into another gem. I
tried adding that gem but it still kept preventing the app from starting
up. I figured we could just go without that then
Remove coupled routes

Rails 4 doesn't allow that anymore, e.g. `root` was defined in both
backend and frontend gems

[Fixes #3146]