Feature #11834: Migrate our infrastructure to Puppet 4
Make our Puppet code compatible with the "future" parser
This will be the first necessary step towards migrating to Puppet 4.
My plan (based on https://docs.puppet.com/puppet/4.5/upgrade_major_pre.html#enable-the-future-parser-and-fix-broken-code) is to set up a Puppet environment (cloned from our production one) with the future parser enabled and test each of our systems with it, one after the other, so that I have an initial list of problems I shall fix. I'll minimize how long each system is managed by this test environment. Then I'll fix these issues, push to that test environment, rince and repeat until I can enable the future parser on our current Puppet 3.x production environment, which should ensure we don't write new code that's not compatible with it.