Add rustfmt to normalize formatting

[antgamdia]

Description of the change

Similary, as we already to in js and go (I guess), this PR brings the configuration for the rust prettifier, the rustfmt tool. It implements the Rust Style Guide.

Benefits

We'll have a consistent code formatting config so that multiple devs have the same linitng rules.

Possible drawbacks

N/A

Applicable issues

N/A

Additional information

I've used the default config for the generation of the .rustfmt.toml feel free to suggest other configurations.

[absoludity]

Thanks! I actually thought I had rustfmt running in vscode on save, but obviously not :)

[absoludity]

If these are all defaults, can we not specify them instead? (ie. I think it's much easier to reason about if this file only has the exceptions to the defaults that we want, if any)

[antgamdia]

Yes, I agree. I just wanted to commit all the options to discuss if we should change something else.
However, these options can be retrieved from rustfmt --print-config default

Thanks! I actually thought I had rustfmt running in vscode on save, but obviously not :)

I thought the same, but I broke something in my vscode config and it stopped working. Then I realized I was using the default formatter in vscode and not the rustfmt one.