fix(help): `deis help` lists all available commands

`deisctl` needs separate usage strings for each command, but for now enumerating all the available commands in `deisctl help` is the least we can do.

Closes #86, refs #83, #36.
can you change this to

```
deisctl config <component> <get|set> <args>
```

it would help users better understand how to use this command :)