integrate car/ cli into cmd/car

[willscott]

• Flesh out the verify command with v2 checks
• The list command is already present
• Removes the header command that previously printed out a json representation of a header. It's unclear what we got from that and what we want to have that do with v2 files. I believe the functionality should be largely maintained, and would prefer to either print relevant data as part of verify or add an inspect command that provides info on both the v2 and v1 metadata if we decide there is important functionality to maintain there.

[rvagg]

👌 ftr I'm not convinced of the utility of verify either, your call on what to remove, as long as we get rid of the old main then this is good by me

[willscott]

I think i imagine keeping verify as a baseline for testing that mutation sub-commands generate reasonable output