Forward Rust (de-)serialization of transparent datatypes (#6793)

### What

Remove lots of redundant serialization code by forwarding transparent
components to its datatypes:

* forward `from_arrow_opt` for fully transparent types
* forward `from_arrow` for fully transparent types
   * this requires us generating it for `datatypes`! 
* the forwarding uses `bytemuck` when possible. Should be possible in
more places, but the constraints are complicated so this isn't fully
automated and depends on types being manually marked as `bytemuck::Pod`
* would be really nice though if we could automate that. Almost
everything we're dealing with _should_ be pod 🤔
* forward `to_arrow_opt` for fully transparent types
* forward `arrow_datatype` for fully transparent types


@ reviewer: There's only two non-generated files:
* `crates/re_types_builder/src/codegen/rust/api.rs`:
https://github.com/rerun-io/rerun/pull/6793/files#diff-4eb7d4aa8c72b1987ed00d1ad9c61782b9dd55d8b96a50a44156388fea8c67f9
* `crates/re_types_builder/src/codegen/rust/deserializer.rs`:
https://github.com/rerun-io/rerun/pull/6793/files#diff-91844032ca93ef2e29de6a660674273bfd6e836b26ae58c83fef09dcd8db1076
Everything else is generated via those changes. You'll want to have a
sampling of both datatypes & components.

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[rerun.io/viewer](https://rerun.io/viewer/pr/6793?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
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