Brainhack Global 2023 project selection

[Lestropie]

Pinging all @MRtrix3/mrtrix3-devs for opinions / ideas.

I should probably get to the Brainhack event in Sydney this year. And should select an appropriate MRtrix3 project to pitch here. So need something Python-based (C++ project takers would likely be nil) that can be largely done by several people in three days.

Ideas (please nominate anything else that comes to mind) (see also prior Hackathon discussion in #1964):

1. Estimation and correction for within-series signal drift (and potentially also better inter-series correction): dwicat: Potential enhancements #1741

2. nibabel MIF / MIH support: Some code written in nibabel: .mif support #2087, but would be nice to bring it up to date, test, and push.

3. C++, but thought I might list anyway: dwidenoise enhancements. Modify rank estimation (dwidenoise: Modified rank estimation #2591); facilitate two-pass approach (ENH dwidenoise: Two-pass approach #2274); spherical kernel (ENH dwidenoise: Spherical kernel #2742); handle >4D data (easier for multi-echo fMRI denoising)
   Edit: Add soft thresholding of PCA components.