Donate function-sdk-rust to crossplane-contrib

Hi!
I've created [function-sdk-rust](https://github.com/jonasz-lasut/function-sdk-rust), which is a Rust SDK that allows user to create composite functions. It's modeled on function-sdk-go and function-sdk-python and I've been using it for personal projects and decided to open-source it.

Details as per governance note:

Name: function-sdk-rust

Purpose: A useful alternative to function-sdks for Go, Python or TypeScript due to Rust's low resource footprint, strong typing and amazing compiler support, which makes writing functions extremely easy. It also makes agentic development of functions easier due to how strict Rust's compiler is

Maintainer team: Just me right now, open to adding more maintainers if the community adopts this sdk and wants to see Rust supported as one of the official languages for function development.

Long term commitment: I'm involved with Crossplane ecosystem and I'm a maintainer of multiple different providers for a long period of time and I plan to continue my work on the ecosystem. I'm also open to add model generation in crossplane/cli for Rust and add documentation examples in all cases where we have Go/Python/Go-templates examples

Start by reviewing the linked function-sdk-rust repository and comparing its scope with function-sdk-go and function-sdk-python. Check the governance requirements for accepting a new SDK, including maintainership and long-term support. Done means the organization has decided whether to accept the SDK and recorded the required ownership and support commitments.

Written by the indexing model from the issue text.