Allow group read access to Puppet private key for use with Foreman or proxy
Add /usr/share/puppet/modules to common modulepath, it's a Puppet default
Various puppet-lint and other style fixes
Move puppet user creation to install

Defining the user puppet in config causes a dependency cycle if the user is
using git_repo=true:

(Exec[restart_puppet] => Class[Puppet::Server::Passenger] => Class[Puppet::Server::Config] => User[puppet] => File[/etc/puppet/rack/config.ru] => Class[Puppet::Server::Passenger])

By moving it to install we ensure it's already there.
Variable interpolation is unpredictable in cron, removing
Archlinux fixes
Puppetagent now renamed to puppet