List: move these things upstream to PyTorch, Funsor, etc.

This issue tracks Pyro components that should be moved to upstream dependencies.

Move to PyTorch

• constraints.IndependentConstraint
  • usage in MultivariateNormal
  • usage in dist.Independent
• dist.Delta #1781
• constraints.integer
• Geometric.log_prob() as patched in pyro/distributions/torch.py
• Uniform's ._unbroadcasted_* logic
• _with_cache() in pyro/infer/reparam/unit_jacobian.py
• dist.DirichletMultinomial https://github.com/pytorch/pytorch/issues/56030

Move to Funsor

See also https://github.com/pyro-ppl/funsor/issues/362

• distributions.util.detach()
• ops.tensor_utils.haar_transform() and .inverse_haar_transform()