feat(Vagrantfile): alter configuration to allow use as Docker host vm

turning off guest additions and vboxsf makes this possible, which is taken directly from the default docker host configuration: https://github.com/mitchellh/vagrant/blob/master/plugins/providers/docker/hostmachine/Vagrantfile
Merge pull request #115 from shopkeep/allow-docker-host-vm

feat(Vagrantfile): alter configuration to allow use as Docker host vm