devel/bear: Upgrade to 4.0.1

The bear project has been re-written in Rust from 4.0.0. We upgrade this
to 4.0.1 and use builtin USE_CARGO.
A good new is that the new version does not need the per-compiler wrapper now.

Also, let aokblast@ take the maintainership.

Approved by: lwhsu (mentor)
Differential Revision: https://reviews.freebsd.org/D54755