Add templated Load() methods to mitk::IOUtil
Summary:
Remove LoadImage, LoadSurface, and LoadPointSet methods, which were added
accidentally after the other overloads of these methods were already
removed.
Replace LoadImage with Load<Image> and so on
Replace casted calls to mitk::IOUtil::Load()
Test Plan: ALL_BUILD
Reviewers: goch
Maniphest Tasks: T24545
Differential Revision: https://phabricator.mitk.org/D112