Qsm-forward

- Improved BIDS compliance: made session and run entities optional; added acq entity, improved argument parsing in CLI, now using derivatives directory for 'derived' types such as masks, segmentations and fieldmaps; also used suffixes correctly including `_Chimap`, `_fieldmap`, `_dseg` and `_mask`, including the `_desc-` entities when multiple derivatives are generated that would otherwise clash.
- Removed docs since they were difficult to maintain with minimal effort - the docstrings on the functions are good enough for now and the examples should make it clear how to use the software

- The `generate_susceptibility_phantom` function is now imported correctly
- The BIDS suffix can now be changed to support other weightings e.g. `T1w`, `PD`, etc.
- Can now set whether to export phase images or not

- When images are cropped or resized, the same image is returned if the intended resolution or voxel size are the same
- Fixed an error when phase offset production is disabled
- Improved JSON output to include more reconstruction parameters