Add virtualenv configs for stagecraft and admin

I'm unsure if we are happy to merge this as it is, because it will fail if you 
dont have the repo checkout out. I did try using the Vcsrepo define, but it 
seemed to have issues with shared folders, and would also add a lot of time to
the puppet run

 - Creates the virtualenv so workon $projectname will work
 - Installs the requirements.txt
 - Exports required environment variables to run the project
 - Sets a project dir so workon $projectname will cd to correct
   directory