Ignore .vagrant directory
Use vagrant file provisioner for dotfiles

This is amazing - many thanks to contributors on this thread:
https://github.com/mitchellh/vagrant/issues/3021

Copies in .gitconfig and .vimrc from the host, and only if they
exist.

Also chdir to /vagrant and enable apt-get update on start.
Also provision .vim directory for my vimrc
More absolute path hackery to get this to work.

Now cd's to the directory vyos-build-ami.sh is in, and
then the ansible playbook assumes we're always there.