Split layouts into a commons crate

[AdamGS]

Rationale for this change

Step 1 trying to break some of the core crates out into smaller core crates that pull less stuff.

This will both improve compile times and cache usage as the core crates will change less often.

I've tried to make sure the public API of vortex-layout doesn't change, and I'll verify it again before this PR is ready for review.

[codspeed-hq]

Merging this PR will regress 3 benchmarks

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚡ 4 improved benchmarks
❌ 3 regressed benchmarks
✅ 2030 untouched benchmarks
⏩ 46 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	decompress[u64, (10000, 4)]	310.2 µs	401.6 µs	-22.76%
❌	Simulation	take[small_m/shuffled/primitive/nonnull/chunks=16384/indices=16]	1 ms	1.2 ms	-11.4%
❌	Simulation	decompress[u64, (1000, 16)]	64.4 µs	72.6 µs	-11.3%
⚡	Simulation	cold_misaligned[(64, 256)]	5.1 ms	4.4 ms	+16.53%
⚡	WallTime	words_gather_scalar[65536]	9.4 µs	8.3 µs	+13.67%
⚡	Simulation	compress_fsst[(1000, 64, 8)]	1.2 ms	1 ms	+12.98%
⚡	Simulation	compress_fsst[(10000, 64, 4)]	9.7 ms	8.6 ms	+11.83%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing adamg/layout-split (996bb2c) with develop (93b0535)}

Footnotes

1. 46 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[joseph-isaacs]

On naming I like vortex-layout and vortex-layout-core (second contains the impls of specific layout readers)?

I don't like core but it matches the editions that these features should be added too.

[AdamGS]

I also think core is more appropriate here