Cpp: Update to match the FindIce macro behaviour

Additionally, include links to the upstream cmake documentation
and add common cmake search variables which might be required.
merge develop -Dorg -Ssuccess-only: PR 947 (Cpp: Update to match the FindIce macro behaviour)
merge develop -Dorg -Ssuccess-only

Repository: openmicroscopy/ome-documentation
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Merged PRs:
  # PR 947 rleigh-dundee 'Cpp: Update to match the FindIce macro behaviour'

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