add data preprocessing notebooks into library as scripts

[ssenan]

• Resolves add filter master data to library  #217
• Converts main dataset curation and preprocessing notebooks into scripts for library
• Provides tests for all new functionality + updates/removes some old placeholder tests

[codecov]

Codecov Report

Merging #221 (c780c9d) into main (110eba8) will increase coverage by 4.44%.
The diff coverage is 66.03%.

@@            Coverage Diff             @@
##             main     #221      +/-   ##
==========================================
+ Coverage   30.67%   35.12%   +4.44%     
==========================================
  Files          20       21       +1     
  Lines        1167     1358     +191     
  Branches      155      180      +25     
==========================================
+ Hits          358      477     +119     
- Misses        804      874      +70     
- Partials        5        7       +2     

Files	Coverage Δ
src/dnadiffusion/__init__.py	100.00% <100.00%> (ø)
tests/test_data_util.py	100.00% <100.00%> (ø)
tests/test_preprocessing.py	100.00% <100.00%> (ø)
tests/test_validation_preprocessing.py	100.00% <100.00%> (ø)
src/dnadiffusion/utils/data_util.py	46.32% <73.68%> (+10.60%)	⬆️
src/dnadiffusion/data/preprocessing.py	39.21% <39.21%> (ø)

[cameronraysmith]

All of my comments are refactoring notes for the future.