add extra "always-allow" cli argument

[khaerensml6]

The documentation for the "only-licences" argument is a bit vague imo:

--only-licenses ONLY_LICENSES [ONLY_LICENSES ...] List of allowed licenses (packages/dependencies with any other license will fail)

I took this to mean that the licenses provided here would always be allowed, but it appears to still check compatibility for these licenses, even when they're in this list.

Would it make sense to add an additional cli argument that takes an exhaustive list of licenses to always allow, and reject all others? This would give more control to users.