IFormatReader: Remove deprecated methods

Remove methods deprecated in 5.0 for 5.1.  These are getChannelDimLengths, getChannelDimTypes and getCoreMetadata.

This is partly to clean up old unused stuff for 5.1, but to also clean things up to allow the introduction of nD API in both the Java and C++ implementations in the future, where the multiple ways of getting channel information become an unwanted distraction.

There should be no impact on openmicroscopy.git since none of these methods were in used, but marking breaking to avoid potential breakage in case I'm wrong.

--no-rebase
--breaking

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Testing:

ICSReader: Check full-repo-test.  There may be sample files which don't have ModuloC annotations where the channel sizes differ.  We don't currently handle these with Modulo where the channel size list did.  If this is the case, we might want to look at updating the data model to handle this case.
Plugins: Should be transparently using ModuloC in all cases.  But may need testing with e.g. FLIM data or any reading using ModuloC.