Add documentation for working with Python API (as alternative to using YAML files)

It would be nice to have a guide / documentation on how to use the LiR package's Python API as opposed to using the YAML configuration files.

It would be nice to have documentation that describes:
- How to set up the necessary class(es) for creating a LR System
- How to use a pipeline / or multiple pipelines
- How to write results (using custom output / directories / etc.)
- ...