Allow clarifying unlicensed crates as deliberately unlicensed (previously possible in 0.2)

[iliana]

Is your feature request related to a problem? Please describe.
I am working on a project where I've not identified the license I want to use yet, but I still want to use licenses.unlicensed = "deny" to deny unlicensed and unclarified dependencies. Listing a license in either Cargo.toml or deny.toml would be inaccurate if I'm planning on keeping the project history.

Describe the solution you'd like
Maybe Clarification could have unlicensed: Option<true> or the like.

[[licenses.clarify]]
name = "my-neat-project"
unlicensed = true

Describe alternatives you've considered
We're currently locking to cargo-deny 0.2 to keep this functionality as part of the skip key.

[Jake-Shadle]

I could see adding this feature, or maybe even a specific setting for ignoring the root level crate(s).

[iliana]

I’d definitely prefer the top-level “unlicensed top level crates” lint argument, that’s a good approach — happy to implement if there's an agreed-upon config key :)

[Jake-Shadle]

@iliana Oh no, I didn't see offer to implement this! I was thinking of something like ignore-workspace or the like which is just a boolean that defaults to false. If it's true the license check would then just skip any package in this list https://docs.rs/cargo_metadata/0.9.1/cargo_metadata/struct.Metadata.html#structfield.workspace_members (but would probably still emit a Severity::Help that was skipped).