Fix build error on windows due to wrong type Replace more longs

Summary:
Replace some hard coded types by their ITK equivalents.

This sometimes results in build errors on Windows. (happened to me during one superbuild, could not be reproduced later)

Test Plan: Should be covered by quite a few tests as they are very central classes converting images.

Reviewers: kislinsk, O1 MITK Core

Reviewed By: kislinsk, O1 MITK Core

Subscribers: neher

Maniphest Tasks: T22830

Differential Revision: https://phabricator.mitk.org/D49