Static training, postprocessing and inference using engine

.coverage

examples/analytical-function/test_analytical_function.py

src/bayesvalidrox/bayes_inference/bayes_inference.py

src/bayesvalidrox/bayes_inference/mcmc.py

src/bayesvalidrox/post_processing/post_processing.py

src/bayesvalidrox/surrogate_models/engine.py

src/bayesvalidrox/surrogate_models/exp_designs.py

src/bayesvalidrox/surrogate_models/exp_designs_.py

src/bayesvalidrox/surrogate_models/input_space.py

src/bayesvalidrox/surrogate_models/surrogate_models.py