A first draft of the contribution guidelines can now be found in `CONTRIBUTING.md`.
The website was rebuilt, but does not include the guidelines yet.

User guide startet for models, surrogate training, sequential training, postprocessing and BAyesian classes. The guide now contains simplified UMLs (for BayesInf not yet done).

Webpage includes quickstart, user guide, tutorial, example collection and api.
One new example was added for the user guide.

Build api pages with autosummary and modified templates to include class documentation.
Tutorial updated to BVR 1.0.0 (engine use).

Copied the first version of the sphinx documentation into the docs/source folder. It can be built in html format with '.\make html'.
This includes start of API documentation, summaries of the examples and a tutorial for the 'analytical function' example for BVR version 0.0.5.

An example 'principal_component_analysis' was added to specifically test this functionality. It uses the analytical model.
Fixed two if-calls in `pca_transformation` to match older code and the content of the function.

This reverts commit acf483a1

Split the model comparison to be callable in functions for bayes factors, model weights and justifiability analysis and renamed the overall function

BMC only runs the BME part of BayesInf, split JA into its own function, removed redundant function in MCMC, added to function diagrams

More test for BayesInf, starting tests for MCMC

Some simple fixes for various test, start on testing BayesInf, output directory as changeable parameter in BayesInf