show region in apps list

Feedback from @esebastian reminded me that this would be useful in hk's `apps` command. Here's how it looked before:

```
    $ hk apps
    myapp     user@test.com         Jan 2 12:34
    myapp-eu  user@longdomainname…  Jan 2 12:35

    $ hk apps myapp
    myapp  user@test.com  Jan 2 12:34
```

and after:

```
    $ hk apps
    myapp     user@test.com         us  Jan 2 12:34
    myapp-eu  user@longdomainname…  eu  Jan 2 12:35

    $ hk apps myapp
    myapp  user@test.com  us  Jan 2 12:34
```