Filling out initial rubocop support for metadata.rb and the Gemfile.

https://blueprints.launchpad.net/openstack-chef/+spec/lint-and-unit-testing-for-havana
Removing tailor, cleaning up metadata and Gemfile and adding TESTING.md. Will
remove the .rubocop-todo.yml later, once all the other Rubocop support is in.

Change-Id: I44e3e5002b4e152080a01a36ae08451cc2ee0751
Merge "Filling out initial rubocop support for metadata.rb and the Gemfile."