Set virtualbox network to virtio for speed

Revert "remove ec2_ami_2_0_0_1 module so we begin using the one built in"

* No need to download our specific version
* Use officially supplied FF 45

boxcutter/ubuntu1604 needs recent Vagrant, so pin at least 1.8.7

Xenial doesn't have Python 2 that ansible needs, so use ansible-bootstrap.sh to get it, though that might be way more than we need.

Jibsheet/xenial ansible2 mongod fixes

It won't find the old init script and use it the way Ansible1's
service.py did.

Add role for installing Docker tools

Add retry on ssh failure

remove ec2_ami_2_0_0_1 module so we begin using the one built in

This is purely for testing, as running docker inside docker
requires further shenanigans, but at least it'll catch if we
ever break this role.

Correct Package for libssl-dev

Update to ansible 2.x

These are the same versions as what the rest of configuration is currently set to.