(FACT 614) Add structured operatingsystem fact

The first of these commits adds the 'operatingsystem_hash' (name very much pending) structured fact, which incorporates all operatingsystem-related facts into a nested hash. Includes keys for the equivalents of operatingsystem, osfamily, operatingsystemrelease, operatingsystemmajrelease, and the six lsb facts for Linux systems.

The second commit refactors the previously mentioned existing flat facts to resolve by using values from the new 'operatingsystem_hash' structured fact. This ensures that these facts will stay in sync with the new fact, while also maintaining backwards compatibility.
I think the GNU class should be merged with the Linux class (technically LSB is Linux-specific and GNU isn't specific to Linux) and the CumulusLinux class should derive from Linux.