fix(cli): Respect git commit -a original behavior (#376)

[pawamoy]

We don't overload the -a option anymore with a plain git add ..

I have a second commit that adds tests for this fix, but unfortunately it required quite some changes and additions...

[LinusU]

Am I missing something, or couldn't we just pass the -a flag to git when we run git commit?

[pawamoy]

If I understand correctly, any option passed to git cz is passed internally to git commit. But what was done originally when parsing a -a option was to run git add . in the repository. I simply removed that part. This PR does not implement the -a option, it removes the part that was overloading it with git add ..

See issue #376 for reference.