[Rust]: Setup CI steps

[satoshiotomakan]

Description

As we want to write more rust, we will have to ensure the robustness of our implementations. to do this we need cargo caching, run the rust unit tests and display them on the CI, the clippy checks and finally the coverage check.

Checklist

• cargo caching (only for Linux Rust CI)
• run rust unit tests
• unit tests report in the CI
• clippy check in the CI
• coverage check + report CI

TODO

• Consider installing only target required toolchains. For example, install aarch64-apple-darwin x86_64-apple-darwin for iOS CI only.
• Consider caching rust/target between each branch to improve compilation time. We can schedule a clean build every night to recompile the rust/target cache.

Notes

Test coverage requires cargo-llvm-cov package (therefore llvm-tools-preview rustup tool) and nightly toolchain.
Test CI report requires nextest package.
We also use udeps clippy and rustfmt on nightly.

There should a possibility to cache the entire ~/.cargo directory to avoid recompilation each time.
For now, I use sccache to cache some crates.

[satoshiotomakan]

Test coverage requires cargo-llvm-cov package (therefore llvm-tools-preview rustup tool) and nightly toolchain.
Test CI report requires nextest package.
We also use udeps clippy and rustfmt on nightly.

It takes about 12 minutes to install all of the packages and tools, so I decided to cache the entire ~/./cargo directory after the tools/install-rust-dependencies script.

[satoshiotomakan]

@Milerius @hewigovens could you please take a look at this PR?

[Milerius]

Non-blocker comments, approved - I'm ok to have a separate CI for Rust, will facilitate the transition.

[hewigovens]

Looks good to me, can we cache for other pipelines as well?

[satoshiotomakan]

I haven't checked if the sccache may improve the performance significantly for other pipelines.
I would like to check it as a part of this suggestion #3044

Looks good to me, can we cache for other pipelines as well?