Add `lowest_common_ancestors` algorithm #158

Job	Run time
checks / check-style	2m 3s
changed-files / Check changed files	9s
checks / other-checks	35s
conda-python-build	0s
wheel-build-nx-cugraph	0s
conda-python-tests	0s
wheel-tests-nx-cugraph	0s
pr-builder / run	1s
	2m 48s

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