ENH: Update extension metadata (#15)

Fix import error and remove unused imports

Use generic import for transforms names

Specify that the Preview Release of Slicer should be used

Stop asking for confirmation during tests

Add link to CDash

Stop trying to show console during tests

Update methods calls to install TorchIO

Remove keywords from BibTeX

Delete FUNDING.yml

Downsample icon to avoid Slicer crash

Add abstract module and use SlicerPyTorch

Fix argument name

Stop showing dialogs if testing is enabled

Update README