t589: refactor registry API - deploy trust wrapper

 * removed the old way to extend the default URLs to include
   custom methods and the TrustwrapperResource.install() method
 * add a new field to the Trustwrapper Model and API Resource,
   ``active_task``. This is to relate to the task executing to
   deploy the trust wrapper
 * override default ModelResource.obj_create() with a bunch of
   custom bits.. we first call the original obj_create(), then
   we spawn the async deploy task and update the bundle with
   this information
 * a few corrections of different types

[1] https://redmine.idhypercubed.org/issues/589