Add `LogStateVector` model that stores the log- of the wavefunction

Created by: PhilipVinc

With the recent release of jax 0.3.17 we can now officially use callbacks inside of our models.

So I can finally contribute this.

It's exponentially costly, but it is handy sometimes to check if the problem is the sampling or something else. Also, in combination with ExactState (which in hindsight should have been called FullSummationState), it allows to have a 100% exact state in our calculations.