Add norpm package provider and helper class.

Add norpm package provider and helper class.

This patch adds a new norpm package provider that extends the
Puppet provided default RPM package provider and stubs out
all of the package install, update, purging so that no
packages will get installed. This may be useful when
deploying pre-built images where we effectively just
want to use Puppet for configuration (not installation).

Includes a ::tripleo::package_provider class that will assist
in cleanly disabling package installation via hiera.