Merge branch 'standalone-vagrantfile' into 'master'

Merge branch 'standalone-vagrantfile' into 'master'

Standalone Vagrantfile

@mvdan @CiaranG as a follow up on our work moving to a 64-bit build server VM, this moves the buildserver config to a standalone YAML file and commits a static _Vagrantfile_ to git.  This makes it a lot easier to work with, especially for people who normally use git.  The buildserver config is already a Python _dict_, and its trivial to export a _dict_ to a YAML file.  _Vagrantfile_ is a Ruby script, where its trivial to load a YAML file.  This moves some of the logic into _Vagrantfile_ itself.  This means that someone can mess with _Yagrantfile.yaml_ and/or _Vagrantfile_ to work on the buildserver setup, without having to run `./makebuildserver`.  Then once something is working, it can be ported to the current `./makebuildserver` setup that generates _Vagrantfile.yaml_.

This is important for working on getting this whole thing running in a KVM instance like jenkins.debian.net and elsewhere.  From what I read, VirtualBox in KVM is only possible if VirtualBox is running in 32-bit mode, so that's a dead end for us.  We need to be able to run the buildserver as KVM in KVM #190.  This merge request doesn't get us there yet, but it makes the process a lot easier.

This also moves everything but Kivy to provisioning shell scripts, since the existing chef scripts were really just shell scripts wrapped in Chef wrapped in Vagrant wrapped in `./makebuildserver`.

This passes the gpjenkins CI build that creates the buildserver from scratch, then builds F-Droid and AdAway:
http://qssio5fppcrojdh3.onion:8080/job/fdroidserver-makebuildserver-eighthave/602/

I tried adding Amaze and Retrolambda as test apps for the buildserver too, we'll see how that goes:
http://qssio5fppcrojdh3.onion:8080/job/fdroidserver-makebuildserver-eighthave

See merge request !144