Allow for disabling repository configuration

[mwhahaha]

This change moves the repository configuration to it's own class so it
can be included externally and excludeded if necessary. As part of this
change, the inclusion of rspec-puppet-facts was done to simplify testing
support os configurations.
See https://github.com/mcanevet/rspec-puppet-facts for details on how to
work with rspec-puppet-facts. By default it uses the metadata.json for
the supported operating systems. Since 14.04 is not a supported
configuration based on the failure in ::opendaylight, this has also been
updated to reference 16.04 as a supported version.

[dfarrell07]

This is great refactoring, thanks!

The inline docs and tests look perfect. Would be good to add docs for the new param in the README.

+1 on updating that Ubuntu version in metadata.json, I had a TODO to scrub for old versions with that one in mind.

This does part of #136, and generally cleans up the related logic. It I think the easiest way to resolve the conflict between the two is to merge this larger change and then expose the rpm_repo_enabled param and add rpm_baseurl param as #136 does (edit: if we want to go that way, looking at the original issue #135 it seems like this change may be what was really desired).

This passes bundle exec rake acceptance_[dock,vm].

[itzikb-redhat]

@dfarrell07 Hi, Is it possible to create a new release with this PR ?
Thanks