Merging CDI documentation to ftag-docs master branch
This merge includes:
- New high-level CDI documentation, explores concepts of calibrations, etc.
- Instructional documentation, on how to inspect and create CDI files
- Low-level documentation on systematic strategies
- xAODBTaggingEfficiency package descriptions, containing hopefully useful information and examples
- Automated CDI files scale-factor and efficiency map plotting CI/CD pipeline