[PRQ#50362] Merge Request for itk

MarsSeed [1] filed a request to merge itk [2] into insight-toolkit [3]: Eliminating duplication. 'insight-toolkit' has been on AUR for much longer, and also aligns better with Arch package guidelines, which recommend that a package name should reflect upstream's release tar name. Which, in this case, is InsightToolkit. Also 'insight-toolkit' is maintained much more competently; 'itk', for example, omits needed dependencies like python. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/itk/ [3] https://aur.archlinux.org/pkgbase/insight-toolkit/