Add Catalog Alignment class and functions

[smcguire-cmu]

Change Description

Creates the CatalogAlignment class to represent the alignment between catalogs. This includes a table with the pixel-to-pixel mapping between the files in each catalog, and the resulting tree from selecting the highest level of partitioning in each branch.

Adds functions to compute the alignment between catalogs. This includes adding functionality to the PixelTreeBuilder class.

resolves #9

• My PR includes a link to the issue that I am addressing

Solution Description

The algorithm to perform the catalog alignment is described in detail in this design document

Code Quality

• I have read the Contribution Guide
• My code follows the code style of this project
• My code builds (or compiles) cleanly without any errors or warnings
• My code contains relevant comments and necessary documentation

New Feature Checklist

• I have added or updated the docstrings associated with my feature using the NumPy docstring format
• I have updated the tutorial to highlight my new feature (if appropriate)
• I have added unit/End-to-End (E2E) test cases to cover my new feature
• My change includes a breaking change
  • My change includes backwards compatibility and deprecation warnings (if possible)

[jeremykubica]

I went through the design document and it clarified some of my questions. Thanks!

[codecov]

Codecov Report

Merging #110 (2a6688c) into main (6c11c4b) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #110      +/-   ##
==========================================
+ Coverage   99.83%   99.85%   +0.02%     
==========================================
  Files          41       44       +3     
  Lines        1181     1382     +201     
==========================================
+ Hits         1179     1380     +201     
  Misses          2        2              

Impacted Files	Coverage Δ
src/hipscat/catalog/__init__.py	100.00% <100.00%> (ø)
...catalog/association_catalog/association_catalog.py	100.00% <100.00%> (ø)
src/hipscat/catalog/catalog.py	100.00% <100.00%> (ø)
src/hipscat/pixel_math/healpix_pixel.py	100.00% <100.00%> (ø)
src/hipscat/pixel_tree/__init__.py	100.00% <100.00%> (ø)
src/hipscat/pixel_tree/pixel_alignment.py	100.00% <100.00%> (ø)
src/hipscat/pixel_tree/pixel_alignment_types.py	100.00% <100.00%> (ø)
src/hipscat/pixel_tree/pixel_node.py	96.42% <100.00%> (+0.27%)	⬆️
src/hipscat/pixel_tree/pixel_tree.py	100.00% <100.00%> (ø)
src/hipscat/pixel_tree/pixel_tree_builder.py	100.00% <100.00%> (ø)

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[jeremykubica]

This looks really good. The new comments make it easier to follow and the tests have good cases.

I added one suggestion to the tests.