Create Example Notebook files showcasing the explanation methods

[mmschlk]

The examples currently sitting in the root of the projects should be moved into notebooks and run to showcase the explanations. For this the visualization (#29) and the validators (#24) need to be updated first.

[mmschlk]

Added basic_usage.ipynb in 7ff51c7.

Still need the following notebooks:

• [ ] storage mechanisms (show all kinds of storage mechanisms, how they work and what they do)
• [ ] how to work with sklearn models and what do with data preprocessing -> sklearn pipelines
• [ ] how to work with torch models and what do do with data preprocessing -> torch onehot encoding and such
• [ ] an example notebook with batch / interval / incremental explainers