WIP: Catalog.from_flat

[dougbrn]

Closes #434

#434 has helpful commentary on dealing with the healpix index and the margin catalogs. My initial implementation handles the healpix index by selecting the lowest healpix index for each object, but handles the margins independently from the data. The primary concern for this I would think is for multiple observations of the same object with some jitter in ra/dec, causing some observation to fall into the margin for an object that is in the main catalog. So we would ideally like to collect all measurements so as not to duplicate objects between the margin and main catalog.

[codecov]

Codecov Report

❌ Patch coverage is 15.38462% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.89%. Comparing base (e504fb4) to head (c90a841).
⚠️ Report is 13 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lsdb/catalog/dataset/healpix_dataset.py	10.00%	18 Missing ⚠️
src/lsdb/catalog/catalog.py	33.33%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1215      +/-   ##
==========================================
- Coverage   96.65%   95.89%   -0.77%     
==========================================
  Files          45       45              
  Lines        2841     2875      +34     
==========================================
+ Hits         2746     2757      +11     
- Misses         95      118      +23     

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[github-actions]

Before [31ab3c8]	After [b1a67d0]	Ratio	Benchmark (Parameter)
30.1±0.3ms	33.5±10ms	~1.11	benchmarks.time_box_filter_on_partition
108±1ms	111±1ms	1.03	benchmarks.time_kdtree_crossmatch
175±2ms	180±1ms	1.03	benchmarks.time_open_many_columns_list
50.6±1ms	52.2±1ms	1.03	benchmarks.time_polygon_search
8.38±0s	8.58±0.02s	1.02	benchmarks.time_lazy_crossmatch_many_columns_all_suffixes
389±3ms	396±4ms	1.02	benchmarks.time_open_many_columns_default
8.53±0.01s	8.57±0.09s	1.01	benchmarks.time_lazy_crossmatch_many_columns_overlapping_suffixes
3.92±0.03s	3.92±0.02s	1.00	benchmarks.time_open_many_columns_all
7.09±0.05s	7.02±0.03s	0.99	benchmarks.time_create_large_catalog
1.07±0.01s	1.06±0.01s	0.99	benchmarks.time_create_midsize_catalog

Click here to view all benchmarks.