Create a Rust runtime for LB Prelude

[szg251]

Closes: #103

Some notes on the implementaton:

nix integration

I used nix-cargo-integration (which builds on dream2nix). This hides a lot of complexity with reasonable default configurations. It also uses flake-parts, so making the build.nix a flake module seemed like a natural choice, but it diverges from the current status quo, so there's a separate issue to bring everything to the same conventions.

Types

Integer: num_bigint is used in cardano_serialisation_lib
ByteString: &[u8] or Vec<u8> are the obvious choices, I'm not sure if there's too much difference from the end-user standpoint.

Json serialisers

I followed the same principles that we used in Hs and Ps packages: to_json instances serialise to a Value (intermediary JSON representation). However I'm not sure, if this is the most convenient way from the end-user perspective, we will have to experiment with this later.

Another question mark is error messages: I'm still not familiar with the messages serde returns, so I basically copied the error messages from the Haskell implementation. To make this library feel more natural, I think these should be adjusted in the future.

Property testing

There are two popular options in Rust for property testing: quickcheck and proptest.
The former is a simple library, mostly following the Haskell implementation and design principles. proptest is a more robust (and a little bit slower) tool, with a lot of nice features.
I decided to go with the latter one, as it allowed me to write simply implement BigInt generators. Also, I simply liked the API of the library.
One area which is still not clear to me is proptest-regressions. When a proptest fails, the input values are stored in the project directory, and used in later tests. I decided to put this into .gitignore, I'm not exactly sure if this is working exactly as I desired (e.g. these tests logs remain even if I change the tests).

Links to related issues

• Adding rustfmt to pre-commit-hooks #109
• Moving all Haskell and PureScript packages to flake modules #110

[bladyjoker]

Great freaking job! Left some comments, let me know wdyt.

[bladyjoker]

This is lovely!

Let me know if you need help syncing this with main.