Enable cern_legacy_facts lint gem
A new cern_legacy_facts lint module has been added to
in particular look for $::operatingsystemmajorrelease and
$facts['operatingsystemmajorrelease']
The module can be extended later for any other facts we are trying to get rid of.
https://gitlab.cern.ch/ai-config-team/puppet-lint-cern_legacy_facts-check
the module is very much inspired by