Ref #3897 - dynamic bindings

Switch to dynamic bindings. This PR replaces static apipie bindings with the new dynamic ones (https://github.com/Apipie/apipie-bindings). The set of changes is big and I expect some further tuning and discusion.

What needs to be resolved:
- better handling of missing resources
- packaging of the bindings, activesupport on ruby 1.8
- foreman plugins integration, especially katello