Pre-factor to simplify hats loading

[delucchi-cmu]

Complements (and requires) astronomy-commons/hats#394

Closes #460.

Puts all the file reading on loading a catalog into a single module. This reduces the complexity for reading the code, reduces code duplication, and also reduces the number of times we need to read the properties file, and perform file system stat calls to determine if files exist. This should speed up catalog loading on remote file systems where there is a latency associated with each file read.

Enough of the code has changed, that we no longer need the additional (and mostly unused) argument for catalog type, in order to appease mypy type checking.

[codecov]

Codecov Report

Attention: Patch coverage is 98.90110% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.65%. Comparing base (f1a3713) to head (0ebb3e8).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lsdb/loaders/hats/read_hats.py	98.83%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #461      +/-   ##
==========================================
- Coverage   97.71%   97.65%   -0.06%     
==========================================
  Files          44       39       -5     
  Lines        1619     1537      -82     
==========================================
- Hits         1582     1501      -81     
+ Misses         37       36       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[github-actions]

Before [f1a3713]	After [4aa3b83]	Ratio	Benchmark (Parameter)
failed	17.7±0.2ms	n/a	benchmarks.time_box_filter_on_partition
failed	14.4±0.08s	n/a	benchmarks.time_create_large_catalog
failed	2.16±0.01s	n/a	benchmarks.time_create_midsize_catalog
failed	105±0.8ms	n/a	benchmarks.time_kdtree_crossmatch
failed	32.4±0.7ms	n/a	benchmarks.time_polygon_search

Click here to view all benchmarks.