feat(corectl): Publish machine IP in list-machines cmd

New output looks something like this:

```
$ corectl list-machines
MACHINE					IP		METADATA
c3156d95-77a6-420a-8555-63d1b5a3b58b	54.193.91.38
b87a29ef-0d62-4957-9794-3ebc9c950133	54.193.43.67
8692d826-0233-4bc8-84e8-294fd2071746	54.193.92.223
```