ENH: remove unused vtkXNATPermissionPrompter class
ref: https://discourse.slicer.org/t/slicer-5-0-deprecation-discussion-wiki/2377
I checked all registered (git-based) extensions by cloning all [1] and then grepping for vtkXNAT
The only remaining svn extensions are below, and they probably don't use XNAT.
ABC.s4ext IntensitySegmenter.s4ext MarginCalculator.s4ext Scoliosis.s4ext
[1]
for f in `grep -rl "scm git" ExtensionsIndex/`; do
url=`cat $f | grep scmurl | cut -d" " -f2`
git -C sources clone $url --depth 1
done