1446 add api for guidance

[manuelgloeckler]

This adds an API for post-hoc modifications of the trained score estimator, allowing modifications of the likelihood or prior, the support, or other additional constraints. This addresses issue #1446 .

To does:

• Adds general API inline with current iid_method
• Refactor the parameterizations from stringly type to strongly typed (also for iid!)
• Adds some useful explanatory guidance approaches:
  • Classifier free guidance
  • Universal guidance - interval truncations.

[codecov]

Codecov Report

❌ Patch coverage is 91.72932% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.79%. Comparing base (28f3deb) to head (0476ab0).

Files with missing lines	Patch %	Lines
sbi/inference/potentials/score_fn_util.py	91.89%	9 Missing ⚠️
sbi/inference/potentials/vector_field_potential.py	90.90%	1 Missing ⚠️
sbi/utils/score_utils.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1482      +/-   ##
==========================================
- Coverage   87.89%   83.79%   -4.10%     
==========================================
  Files         134      134              
  Lines       11168    11286     +118     
==========================================
- Hits         9816     9457     -359     
- Misses       1352     1829     +477     

Flag	Coverage Δ
unittests	83.79% <91.72%> (-4.10%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sbi/inference/posteriors/vector_field_posterior.py	71.53% <ø> (-8.03%)	⬇️
sbi/inference/potentials/vector_field_potential.py	75.20% <90.90%> (-15.87%)	⬇️
sbi/utils/score_utils.py	91.50% <90.90%> (-0.17%)	⬇️
sbi/inference/potentials/score_fn_util.py	88.81% <91.89%> (ø)

... and 29 files with indirect coverage changes