Add support for cargo-binstall

[proski]

cargo-binstall makes it possible to install crates without compilation: https://github.com/cargo-bins/cargo-binstall
However, cargo binstall stg still compiles the sources.
There is documentation that explains who to point cargo-binstall to the correct location of the binaries:
https://github.com/cargo-bins/cargo-binstall/blob/main/SUPPORT.md

I run cargo-binstall as part of a script that sets up a development container. Compiling stgit is a significant part of that script execution time.