More descriptive output on `cfg status`

[Drake-Eidukas]

With git, when you run git status, it provides really helpful output on how to add / commit files, whereas cfg status is still rather cryptic, especially to a new user of the tool.

drake@element:~/workspace/test_base$ git status
On branch master
Untracked files:
  (use "git add <file>..." to include in what will be committed)

        neet/neet.yaml
        new_test.json

nothing added to commit but untracked files present (use "git add" to track)
drake@element:~/workspace/test_base$ cfg status
## master
?? neet/neet.yaml
?? new_test.json

It'd be nice to have a similar output to git on this one.