feat: Added Gomory–Hu Tree (all-pairs min-cuts via n1 max-flows) (#6818)

* Add Gomory–Hu Tree (all-pairs min-cuts via n1 max-flows)

* Stabilize Monte Carlo integration with antithetic variates to reduce variance

* Fix Checkstyle in GomoryHuTreeTest: remove inner assignments, add braces, split declarations

* SpotBugs: use RandomGenerator interface in test helper

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Co-authored-by: Deniz Altunkapan <deniz.altunkapan@outlook.com>