Update the file and section structure of the project documentation for better readability. Removed 'annotate.md' and replaced it with an expanded 'annotators.md'. The new document provides examples of each annotator and includes preview images for better understanding. The API reference structure was flattened for simplicity and related documents 'core.py' and 'mkdocs.yml' were updated accordingly. The core tracker and dataset documents were renamed for consistency.
SkalskiP