Drupal VM project-specific provisioning

[zendoodles]

This PR adds project-specific ansible provisioning for the Drupal VM. It's against #31, and also includes:

• Changes to config.yml to allow us to use .local and a few other things for consistency with current projects.
• Refactoring of install script. The paths were broken, and I had a hard time following the logic enough to understand how to fix it.
• Moved destination for configs to conf/vagrant to simplify tab completion.

I used this to create a PR on uw-stout swapping in the drupal-vm, and to build the new ama-d8 vm

I still think it would be better as part of the skeleton, but it's obviously feasible here too.

There is still an issue with drush. When called directly it complains about needing a higher bootstrap level to run. It's fine when called by phing (likely because phing explicitly declares the drushrc.php file.) The aliases provided by the drupal vm also work. So drush @ama-d8.ama-d8.local cim -y is fine, but drush cim -y is not.

That should be a pretty easy fix. Otherwise IMO this is ready to go.