Update nodes/php module

The recent release changed the module name
Configure Apt sources to use Ubuntu mirrors

Makes local package downloads much faster
Move Emacs provision into separate class
Fixup ada0e7e
Improve Puppet provisioning dependencies

Split Python and Ruby installation into separate modules. Make sure that
Ruby and Python are available before installing Gems and Pip packages
respectively.  Also make sure that apt-get sources and indexes are up to
date before installing packages.