[DO NOT MERGE] - add capsule support to API/CLI

See http://projects.theforeman.org/projects/katello/activity?from=2014-05-20 for more details on how to use that.

Things to do before merging:

- [ ] - authorization
- [ ] - tests
- [ ] - address PR issues
- [ ] - merge the PRs to katello-installer to fix the capsule installer http://projects.theforeman.org/issues/5815
- [ ] - resolve missing v1 controller causing katello-agent http://projects.theforeman.org/issues/5804 to not be initialized