(FACT 614) Add structured operatingsystem fact

This commit adds the 'operatingsystem_hash' structured fact,
which incorporates all operatingsystem-related facts into a
nested hash. Includes keys for the equivalents of
operatingsystem, osfamily, operatingsystemrelease,
operatingsystemmajrelease, and the lsb-based facts when available
on Linux and kfreebsd systems.
(FACT 614) Sync flat operating system facts with structured fact

This commit refactors operatingsystem, osfamily, operatingsystemrelease,
operatingsystemmajrelease, and the lsb 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.