Allow for direct Dd, Ddt sampling

[martin-millon]

Solve #52

[codecov]

Codecov Report

❌ Patch coverage is 51.47059% with 33 lines in your changes missing coverage. Please review.
✅ Project coverage is 98.00%. Comparing base (3766c78) to head (835334c).

Files with missing lines	Patch %	Lines
hierarc/Sampling/ParamManager/lens_param.py	26.66%	22 Missing ⚠️
hierarc/Likelihood/lens_sample_likelihood.py	61.90%	8 Missing ⚠️
hierarc/Likelihood/cosmo_likelihood.py	80.00%	1 Missing ⚠️
hierarc/Likelihood/hierarchy_likelihood.py	80.00%	1 Missing ⚠️
hierarc/Sampling/ParamManager/cosmo_param.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #53      +/-   ##
==========================================
- Coverage   99.12%   98.00%   -1.12%     
==========================================
  Files          54       54              
  Lines        2848     2911      +63     
==========================================
+ Hits         2823     2853      +30     
- Misses         25       58      +33     

Files with missing lines	Coverage Δ
hierarc/Diagnostics/goodness_of_fit.py	100.00% <100.00%> (ø)
.../Likelihood/LensLikelihood/base_lens_likelihood.py	100.00% <ø> (ø)
...ierarc/Sampling/Distributions/lens_distribution.py	97.22% <ø> (ø)
hierarc/Sampling/ParamManager/param_manager.py	100.00% <ø> (ø)
hierarc/Likelihood/cosmo_likelihood.py	95.76% <80.00%> (-0.73%)	⬇️
hierarc/Likelihood/hierarchy_likelihood.py	96.42% <80.00%> (-0.53%)	⬇️
hierarc/Sampling/ParamManager/cosmo_param.py	99.38% <80.00%> (-0.62%)	⬇️
hierarc/Likelihood/lens_sample_likelihood.py	88.23% <61.90%> (-11.77%)	⬇️
hierarc/Sampling/ParamManager/lens_param.py	92.14% <26.66%> (-7.86%)	⬇️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[martin-millon]

This can work only with time delay lenses since non-time-delay lenses require some Dd/D_ds scaling to obtain the predicted velocity dispersion. This requires a cosmological model, or at least some constraints for the relative expansion history. I think there is nothing to do about this; this is a limitation if one doesn't want to assume a cosmological model. Any thought @sibirrer @ajshajib ?