Apply clippy suggestions and rustfmt to #69

[kylebarron]

This adds clippy linting and rustfmt formatting to the zarr-rs branch in #69

The CI comes from https://github.com/geoarrow/geoarrow-rs/blob/main/.github/workflows/ci.yml. This version uses nightly clippy to enable import sorting. If that's not a priority for you, we can simplify the CI script to use stable clippy.

[alxmrs]

Thanks! This is really useful and in general I agree with your tastes as to what versions we should use. My main note of feedback is: I was thinking of setting up pre-commit fairly soon to unify all the linting / formatting of the project. Do these tools fit in well that setup?

I'm happy to merge this for now and migrate to pre-commit in a later PR.

[kylebarron]

You can use anything with pre-commit, though it's not very common to use pre-commit with Rust projects. E.g. in my projects I only use pre-commit for the Python parts of the Python bindings. But people have made adapters to use pre-commit with Rust https://github.com/doublify/pre-commit-rust. You might want to search for one that's maintained.

[alxmrs]

Thanks for that context! In that case, this PR looks good to me.