Add function to irregularly rebin data in N dimensions (Part 2)

[DanRyanIrish]

This PR continues #109. It tries to create a function that can irregularly rebin an NDCube instance.

To Do

• [x] Update tests, including adding test for rebinned WCS.
• [ ] Add changelog

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 89.75904% with 17 lines in your changes are missing coverage. Please review.

Project coverage is 73.29%. Comparing base (a694ede) to head (95a4da3). Report is 4 commits behind head on main.

Files	Patch %	Lines
stixpy/product/tools.py	87.75%	12 Missing :warning:
stixpy/coordinates/transforms.py	92.64%	5 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #120 +/- ## ========================================== + Coverage 68.92% 73.29% +4.37% ========================================== Files 31 32 +1 Lines 1847 1955 +108 ========================================== + Hits 1273 1433 +160 + Misses 574 522 -52 ```

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