add rustdoc feature support

[TroyKomodo]

• Adds crate_features to be saved as part of CrateInfo
• Adds new flags for rust_doc and rust_doc_test to include the features of the crate when building the docs (enabled by default)

This is my first time using bazel so I am not 100% sure of my work, feedback greatly appreciated.

fixes #511

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[TroyKomodo]

@illicitonion the error here looks spurious

[illicitonion]

Thanks for the test!

I agree the failures look unrelated, unfortunately we have no way of bypassing or rerunning CI ourselves, but if you can push either empty commits or merge-main commits to this branch until things go green, that'd be super handy! (I'd do this myself, but I don't have permission to push to your fork)

[illicitonion]

Oh there is a buildifier error though :)