Extract www.lizard's configuration into a public Puppet repository

Originally created by @intrigeri on #6938 (Redmine)

www.lizard is partly configured with hard-coded manifest snippets and files on the puppetmaster. We need to fix this.

The Jenkins side of things (jenkins.t.b.o, nightly.t.b.o) is covered by tails/sysadmin#7107, so this ticket is about everything else.