Add FUN's Vagrantfile.

This file has two differences with edX's one:

1. Provisionning makes sure that the server-vars.yml ansible playbook
is used.

2. The fun-apps repo is shared between host and guest machines
similarly to edx-platofrm etc.
FUN's private.py django settings module.

This file is imported by the devstack.py settings module.

To make it visible, inside the VM, as the edxapp user:

cd lms/envs

ln -s ../../../fun-apps/private.py
Add the server-vars.yml ansible playbook.

To enable this, in the VM:

cd /edx/app/edx_ansible
ln -s ../edxapp/fun-apps/server-vars.yml