Add bindings for Julia

[bovee]

I don't think there's a good binding library like pyo3 or wasm-bindgen, but this should be doable via straight FFI: https://github.com/felipenoris/JuliaPackageWithRustDep.jl

I'm not exactly sure what the best record format on the Julia side would be? Maybe there's something in their DataFrames library: https://juliadata.github.io/DataFrames.jl/stable/

[bovee]

There appear to be two libraries for binding to Julia and neither can really support this without a lot of work so this might be another year or two off.

• julia-rs is four years old and appears to be unmaintained. It does have all of the low-level jl_ calls though so things like returning errors to Julia are possible.
• jlrs appears to be currently maintained, but allowlists all the low-level calls it/jl-sys generates so it's missing jl_error and a couple other ones (which require nasty workarounds like returning a null pointer for error cases and then checking on the Julia side). It's also not totally clear with its scope/global system how to create a Julia object and then return it back to Julia.