modulesync vars: drop puppet3 , add rubocop_allow_failure and puppet_latest_allow_failure

An unused puppet3 parameter was removed.

Two new parameters can now set be via .sync.yml

• One to make the rubocop test critical
• Second to make the very latest version of puppet critical if it is not already by default.

The following would make both tests critical

.gitlab-ci.yml:
   rubocop_allow_failure: false
   puppet_latest_allow_failure: false

the default that both tests are non-critical remains.