minor enhancements to hammer_cli(_foreman) packaging (DEB)

- set license
- include doc directory into docs
- use config file in the gem (not yet in _foreman gem)
- scratchbuilds:
 - http://ci.theforeman.org/job/packaging_build_deb_dependency/617/
 - http://ci.theforeman.org/job/packaging_build_deb_dependency/618/