Support different deployment sizes (medium vs large) with small coming

Each cf-release, for each CPI, can support 1 or more deployment sizes (different templates).

```
bosh create cf --dns aws.drniccloud.com --ip 54.225.102.129
bosh create cf --dns aws.drniccloud.com --ip 54.225.102.129 --deployment-size medium
bosh create cf --dns aws.drniccloud.com --ip 54.225.102.129 --deployment-size large
```