Use BlobArray and ThinColumn in ResourceData and ComponentSparseSet

[james7132]

Objective

Use less memory overhead when storing resources and sparse set components, maintain less code. Fixes #14824. Supersedes #18245.

Solution

Use BlobArray and ThinColumn to replace BlobVec and Column in ResourceData and ComponentSparseSet. This both uses less memory overhead for each resource and sparse set component we use, and also allows us to avoid keeping two nearly identical implementations of BlobVec/BlobArray and ThinColumn/Column around.

Testing

Tested this against existing unit tests and miri.

Co-Authored By: [email protected]

[james7132]

I ran a set of benchmarks and it doesn't seem to have a tangible improvement to entity insertion or deletion, and we don't have any benchmarks for resource insertion, retrieval, or removal.

The compiler likely was optimizing away the extra branch and panic in the swap_remove. The assembly output seems to have minimally changed.

This otherwise still is a code quality improvement and reduces the overall amount of unsafe code we're maintaining.

[chescock]

Yay, lots of unsafe code removed! The change itself looks good, but I left some nitpicking about comments on the parts that took me a while to understand.