Support non-hpmoc method in case of deprecation

We currently only use hpmoc when calculating the overlap between two MOC sky maps. However, the package doesn't seem to be supported at the moment and we are already seeing warning a deprecations:

../../../usr/local/lib/python3.10/site-packages/hpmoc/arraysetops.py:52
  /usr/local/lib/python3.10/site-packages/hpmoc/arraysetops.py:52: DeprecationWarning: numpy.core.overrides is deprecated and has been renamed to numpy._core.overrides. The numpy._core namespace contains private NumPy internals and its use is discouraged, as NumPy internals can change without warning in any release. In practice, most real-world usage of numpy.core is to access functionality in the public NumPy API. If that is the case, use the public NumPy API. If not, you are using NumPy internals. If you would still like to access an internal attribute, use numpy._core.overrides.array_function_dispatch.
    from numpy.core.overrides import array_function_dispatch

We need to have the prepare for the scenario where hpmoc no longer works with modern versions of numpy by also supporting the previous method of MOC-MOC overlaps (just need to revert some code and add an extra argument).