Since the specs for the type do not use any provider features we do
not have to create a fake provider.

PuppetLabs has released a seperate gem to make writing spec tests easier
(puppetlabs_spec_helper). Using this gem makes a lot of files obsolete
that were initially copied form the puppetlabs/puppet project.

If there is currently no key present in the RPM keyring rpm -q returns
with a non-zero exitcode. This case is now handled properly so no
error message is shown when running puppet.

Because we never really execute rpm and are only testing the provider we
are never asked suitable? so we can just drop a few stubs of FileTest

The rpm_key type was renamed to rpmkey pretty early but the spec
directories should also reflect the new name.

The new type can be used to describe an imported gpg key

Add README and copy the necessary testframework from the puppet codebase