Revert "Remove append_view_path from api ControllerSetup"

Since Api::BaseController inherits from ActionController::Metal we do
need to use append_view_path for rendering views inside api/app/views
and the main app views dir

Extensions should probably also use append_view_path themselves if they
want to override an api template

This reverts commit b0378f5f73927d40a34acb8777b004957588e1aa.
Remove duplicated responder configs and include from api

ActionController::Rendering already includes
AbstractController::Rendering and we had duplicated respond_to calls
in basecontroller and controller_setup