Provide Package for cmd functions

[lordshashank]

We have various important functions in our car cli .
We can provide these utilities in some go-package, as would be quite helpful to people working with car files and building products. We can create package with functions like extract, etc and use them in our cli.

[rvagg]

if you'd like to propose a refactoring that extracts useful functions then please do; I agree that there's a lot of useful functionality bundled up in the cmd package that could be separate—although they are mostly pretty specific to cmd so the utility package should probably be closely related to it, maybe within cmd/ somewhere?

[willscott]

@lordshashank you mentioned extract as a function you'd like factored out. Are there others you'd like to see callable in the same way?

[lordshashank]

Yeah so quite helpful features would be extract, root, verify, filter, inspect (returning report items if possible), and list. I mean if you are going for implementation, there would surely be many interdependent functionalities, maybe provide the important ones. For me use cases are these, maybe someone else have others.