Improved Env command

Cleaned up code a bit, along with creating a basic command structure so now its
`duckpan env <command> <args>` and commands are `get, help, list, rm, set`. 
@moollaza @mwmiller I was planning to throw a few options for these as well, like `rm --all` or `--clobber` for set (asking a default yes_no if env_variable exists), what do you guys think? perhaps for later? Btw the latest update is awesome, the colors and especially, relieving me of that long list of modules loaded (wanted to change that since forever). Idk about this, but i think we should have a changelog for the user who upgrades duckpan, so that they know the highlights of what's new, perhaps we can throw it along with cache or something and create a command for it? or any other simpler way.
I think you need to add `use MooX::Options protect_argv => 0;`

right now `duckpan env --help` tries to check for a command "--help" and it fails:

```
[codio@teresa-misted duckpan {pr/171}]$ duckpan env --help                                                                                                                    
[FATAL]  Command '--help' not found                                                                                                                                           
Available Commands:                                                                                                                                                           
         get:  duckpan env get <name>                                                                                                                                         
         help: duckpan env help                                                                                                                                               
         list: duckpan env list                                                                                                                                               
         rm:   duckpan env rm  <name>                                                                                                                                         
         set:  duckpan env set <name> <value>  
```

I still think the best for this to all be implemented is to follow the `MooX::Cmd` convention which we've already subscribed to for all the top level commands