Implement a new Model class for NIFTy.re
Plus, tweak minor aspects the re.Field class and a Lanczos test.
The old module-image for the shared runners will be discontinued on October 31. All users still referencing gitlab-registry.mpcdf.mpg.de/mpcdf/module-image in their CI pipelines need to switch to the new CI images now, see instructions here.
Plus, tweak minor aspects the re.Field class and a Lanczos test.