Gradient-free-optimizers

- add docstring to public API classes
- add type hints
- drop support for python 3.8

- add support for numpy v2
- add support for pandas v2
- add support for python 3.12
- transfer setup.py to pyproject.toml
- change project structure to src-layout

- add Genetic algorithm optimizer
- add Differential evolution optimizer

- add Grid search parameter that changes direction of search
- add SMBO parameter that enables to avoid replacement of the sampling
- fix bug in transition probability of stochastic-hill-climbing and simulated-annealing

add support for constrained optimization

- add DIRECT algorithm
- automatically add random initial positions if necessary (often requested)