CSV Support

[Luminoth]

Is your feature request related to a problem? Please describe.

Not exactly a problem, but our use case is generally "gather license information and put it in a spreadsheet" so this would be solving a problem for us for sure.

Describe the solution you'd like

It'd be super rad if there was an option to output CSV format instead of HTML.

Describe alternatives you've considered

We've used cargo-license for this in the past, but it would be nice to have it all in one tool and cargo-about / cargo-deny are really the direction we'd like to stick with given their feature set outside of this.

[Jake-Shadle]

FWIW, the template is just handlebars, so technically you could have a template to output csv if you wanted, but that would be cumbersome so I can see adding it as a separate subcommand that outputs CSV/TSV/JSON similarly to how cargo-deny list works.