Add custom reduce to kernels #1920

Job	Run time
Ruff	9s
Conda Pytest Symengine with Loopy FFT	17m 21s
Typos	6s
basedpyright	2m 43s
Conda Pytest	17m 21s
Documentation	2m 54s
Conda Pytest Symengine	17m 21s
Conda Examples	2m 47s
Tests for downstream project pytential	17m 22s
	1h 18m 4s

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