Allow excluding packages from verification with --exclude

[adpaco-aws]

Description of changes:

This PR adds a --exclude option to Kani and allows excluding packages from verification (requested in #2375). It also adds validation for the packages passed to --package and --exclude so we print a user-friendly error with all unknown packages, instead of using expect as we were doing for arguments to --package.

Resolved issues:

Resolves #2375

Testing:

• How is this change tested? Existing tests + 4 new ones.

• Is this a refactor change? No.

Checklist

• Each commit message has a non-empty body, explaining why the change was made
• Methods or procedures are documented
• Regression or unit tests are included, or existing tests cover the modified code
• My PR is restricted to a single feature or bugfix

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

[zhassan-aws]

Thanks @adpaco-aws!

because it doesn't require --workspace (but it's implied anyway)

I'd prefer if we make --workspace required to keep the same interface as cargo build/test.

[adpaco-aws]

I'd prefer if we make --workspace required to keep the same interface as cargo build/test.

Thanks, it's required now.