Deprecate CollectionSizeService (#3099)
Deprecate CollectionSizeService (#3099)

This service searches `child_object_ids_ssim`, which is not used in Hyrax. It
appears to be an unused holdover from older Sufia versions. We are deprecating
now. If developers balk at the deprecation warnings, we'll know we need to fix
it.
samvera/hyrax,samvera/hyrax,samvera/hyrax,samvera/hyrax