lazy_static, if no_std environments were used, effectively required always
using spin locks. This resolves the ergonomics of that while adopting Rust std
code.
no_std does still use a spin based solution. Theoretically, we could use
atomics, yet writing our own Mutex wasn't a priority.
Creates a new monero-generators crate so the monero crate can run the
code in question at build time.
Saves several seconds from running the tests.
Closes https://github.com/serai-dex/serai/issues/101.