Cleanup config

[nathanjmcdougall]

Fixes #292

Also noticed some setuptools config. I don't think this is needed anymore, so I have removed it - the Maturin build backend has its own package finding logic etc. and there are no other references to setuptools in the codebase.

[codspeed-hq]

CodSpeed Performance Report

Merging #293 will not alter performance

_{Comparing nathanjmcdougall:maint/cleanup-config (2002719) with main (ea65558)}

Summary

✅ 26 untouched
⏩ 23 skipped¹

Footnotes

1. 23 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. ↩