Make rulesets delayed (and refactor)

[saulshanabrook]

This PR was started to try to make ruleset registrations delayed, so that they could refer to types that have not been defined yet in the file.

For example, in the array_api.py file, if we have a method of Bool that takes Ints, we want to be able to define that and define the rewrite rules for Bool before the Int is defined.

We do this now by deferring type analysis and rule parsing until a ruleset is used, instead of when it was defined.

Along the way, I ended up cleaning up a bunch of constructs that were left over from the last larger refactor (#108, #111), which moved functions/classes away from the EGraph.

[codspeed-hq]

CodSpeed Performance Report

Merging #130 will degrade performances by 16.6%

_{Comparing refactor (2b25475) with main (df4e1d8)}

Summary

❌ 1 (👁 1) regressions
✅ 6 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	refactor	Change
👁	test_source_optimized	42.9 s	51.4 s	-16.6%