Set default modulepath to '/etc/puppet/modules:/usr/share/puppet/modules'

When I setted up puppetmaster by [theforeman/puppet module](https://forge.puppetlabs.com/theforeman/puppet), I got default puppetmaster configuration without _environments_ (there is always _production_ enviromment by default).

As I can see, the Linux distributors placed packaged puppet modules in _/usr/share/puppet/modules/_ directory.

But _smart-proxy_ search modules in _/etc/puppet/modules_ only by default.

It may be usefull to add _/usr/share/puppet/modules/_ into default search path.