Docker for dev and test

Easier to discuss things in a PR so opening one pre-emptively

To test this in a VM (virtualbox):

1.  make sure vagrant >= 1.2 is installed
2.  `vagrant up`
3.  It will tell you to run `vagrant reload` in 2 minutes.  Seriously, wait a bit.  Go get coffee maybe, just to be sure it's done rebooting then installing.
4.  `vagrant reload`
5.  `cd /mnt/shared/otter`
6.  `sudo CC_USER_PASSWORD=... CC_USER_API_KEY=.... CC_NON_AS_PASSWORD=... OTTER_ID_PASSWORD=... OTTER_ID_URL=... OTTER_ID_ADMIN_URL=... docker/runner.sh`

This is for running things in CI - dev/prod will probably be different PR.