Add Cython build infra + initial extension module #37

Job	Run time
Docs, Examples, and Eval	49s
Vanilla Python 3.10 on windows	1m 0s
Conda Python 3.10 on macos	1m 18s
Vanilla Python 3.10 on ubuntu	15s
Minimal Supported Dependencies	7s
Conda Python 3.10 on windows	1m 11s
Vanilla Python 3.11 on windows	51s
Conda Python 3.10 on ubuntu	1m 16s
Vanilla Python 3.11 on ubuntu	19s
Conda Python 3.11 on macos	1m 11s
Conda Python 3.11 on windows	1m 16s
Conda Python 3.11 on ubuntu	1m 16s
Test Suite Results	1s
	10m 50s

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