dependencies and license checking

[orangecms]

@rjoleary made a good point that we should investigate a few things around our dependencies.
They come from various sources, and they have various licenses.

The Fuchsia project has a Rust dependencies license checker:
https://fuchsia.googlesource.com/scripts/+/3p-dart-pkg/rust/check_rust_licenses.py

We should also investigate if our dependencies are up to date, if they are still maintained, if something else has been established here or there, see if we can reduce some to decrease the probability of malicious code sneaking in, etc..