Serve Katello api documentation on '/apidoc` when Katello is loaded

We use the foreman `/apidoc` path to serve the Katello's resources when the
engine is loaded. This allows both Katello and Foreman to use apipie for their
bindings without affecting each other.

There are some issues with loaded the Katello code when loading apidoc. One of
the possible fixes is commenting out `wrap_parameters` call in Foreman's
`config/initializers/wrap_parameters.rb` file. When doing that,
http://localhost:3000/apidoc will serve as the Katello's original apidoc path,
using the api docs from the engine