Ls performance changes

I'd like to make the following changes to the `ls` command for performance reasons:

1. Add a `-q` flag that only returns names. Base58 encoding a bunch of CIDs is actually quite a time-consuming operation. It would be nice to have a variant that just returns names.
2. Replace `--resolve-types` with `--type=[always|local|never]`. Currently, there's no way to say "don't resolve this type, even if we have the object". Having that option would allow us to avoid hitting the datastore for every file listed. (note, `--resolve-types` will only be deprecated, not removed).