Migrate HPF to configuration object and fix BiasConfig serialization

[mdekstrand]

This brings a couple small cleanups from #596:

• migrate HPF to the configuration object design
• fix BiasConfig serialization to sort the entity list for deterministic serialization

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.97%. Comparing base (204dcee) to head (09e05f7).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #600      +/-   ##
==========================================
+ Coverage   89.96%   89.97%   +0.01%     
==========================================
  Files         106      106              
  Lines        6567     6565       -2     
==========================================
- Hits         5908     5907       -1     
+ Misses        659      658       -1     

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