Clean up and minor API changes

[Trybnetic]

This PR introduces some minor changes to the API, does some general clean up and corrects some things in the documentation

The changes especially address:

• Remove the old sleep models from the 2022 manuscript as they are not properly working
• Remove the pytorch dependency as it is not longer needed
• Fixes the labeling of the detect_time_in_bed_weitz2024 function (thanks to @claaslendt for pointing that out!)
• Adds a read_metadata function to only read the metadata of a gt3x file
• Adds an autocalibration module with a calibrate function. However, a reimplentation of the autocalibration function from GGIR is still missing
• Fixes the examples in the documentation
• Adds calculate_enmo as a convenience function