Add algorithm for finding pairs of paths in a node trie (#8286)

Add algorithm for finding pairs of paths in a node trie (#8286)

This is in preparation for cleaning our implementation of care graph computations.

Right now, UF, datatypes, sets, and strings all have copy/pasted versions of an algorithm that creates an index of operators and run the algorithm in the PR for computing care graphs.

Followup PRs will extend the theory interface and add an instance of this class for computing care graphs. Then, we will add optimized care graph computation for bags (which is missing right now), and then perhaps revisit arrays, which appears to have issues in its computeCareGraph method.