Revert "new: methods to check for existence of entities either by URI or sameAs match"
Revert "new: methods to check for existence of entities either by URI or sameAs match"

This reverts commit 5b61f20f31f6103451b26e9aa1310ee91a60ad66.

weblyzard/weblyzard_api,weblyzard/weblyzard_api,weblyzard/weblyzard_api