(19873) Add OS major release fact

Cloning ticket 15714 and submitting new PR with recommended changes to try to get this taken care of.

On RHEL clones and Debian
(Amazon,CentOS,CloudLinux,Debian,Fedora,OEL,OracleLinux,OVS,RedHat,Scientific,SLC)
it would be useful to pull out the major release version

ie 5.8=>5, 6.3=>6, 6.0.3=>6 (this is especially useful when creating URLs for package downloads)

This is available as the lsbmajdistrelease but there are too many dependencies on LSB for minimal installs