ENH: Remove ITK AnalyzeImageIO registration

Originally introduced in r824, the ITK AnalyzeImageIO have been
deprecated. The NIFTI ImageIO implementation is now able to read
analyze .img or .hdr files as well as the original Analyze ImageIO.

From: Bradley Lowekamp <blowekamp@mail.nih.gov>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23660 3bd1e089-480b-0410-8dfb-8563597acbee