Add the Registry to docker-compose.

- Add registry_migrations and registry definitions
- Add configuration & certs for registry
- Add initdb scripting for postgres to create dedicated db 'registry'
- Add configuration to webservice's config.yml.erb

Usage:

Adding the following as `/etc/docker/daemon.json` will allow insecure
access to the any registry that resolves to `127.0.0.1`.

```json
{
  "insecure-registries" : [ "127.0.0.1" ]
}
```