Use Pydantic models for component configurations

[mdekstrand]

This changes the component configuration mechanism to use Pydantic models (or Python dataclasses) instead of ad-hoc constructor parameters, fields, etc.

[codecov]

Codecov Report

Attention: Patch coverage is 97.47191% with 9 lines in your changes missing coverage. Please review.

Project coverage is 89.96%. Comparing base (f077dc7) to head (c6186d9).
Report is 51 commits behind head on main.

Files with missing lines	Patch %	Lines
lenskit/lenskit/pipeline/components.py	91.30%	4 Missing ⚠️
lenskit/lenskit/als/_common.py	96.15%	2 Missing ⚠️
lenskit-implicit/lenskit/implicit.py	94.44%	1 Missing ⚠️
lenskit/lenskit/basic/bias.py	96.15%	1 Missing ⚠️
lenskit/lenskit/basic/popularity.py	93.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #596      +/-   ##
==========================================
- Coverage   90.77%   89.96%   -0.81%     
==========================================
  Files         107      106       -1     
  Lines        6567     6568       +1     
==========================================
- Hits         5961     5909      -52     
- Misses        606      659      +53     

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