Cmake build integration

[tgross35]

I think this would look like the following:

• Add a MYSQL_ADD_RUST_PLUGIN macro
• Macro should check that cargo is available, possibly validate version (not sure what our MSRV is here but I think 1.65 is probably reasonable)
• Dynamic: cargo rustc --manifest-path rust/somepath/Cargo.toml --target-dir rust/target --crate-type=cdylib
• Static: cargo rustc --manifest-path rust/somepath/Cargo.toml --target-dir rust/target --crate-type=staticlib -- --cfg make_static_lib
• --release or based on whether it's a debug build
• Output is in rust/target/debug/ or rust/target/release (can also rename)

Not sure how to handle C code dependency and communicate that with the build system for dynamic, but for static I think it would just work