**BIG** Refactor/Rework
Large refactor/rework of code in prep of going public:
Main changes:
- remove copied jax-cosmo univariate spline code and models that use it
- Add all the Log(X/Y) bases in interpolation.py
- Add kwargs to Basis spline models
- rework env scripts
- change example analysis script
- move injection loading to selection.py
- add plotting/postproc fcts