Introduce and use NoCrossReferencingLexemeStatements
The previous implementation of merge validation would not
catch references to lexemes or sub entities from a variety
of places, for example:
- Lexeme statement reference snak -> lexeme form statement qualifer
- and many more
This new attempt has come from discussion on and about Iaf0582870
which was created to add Sense support for merging Lexeme entities.
T198106 is the origional ticket with the origional BDD for this
decision. It has also been double checked with Lydia and the folks that
worked on NoCrossReferencingFormStatements that I am removing here.
This patch also introduced LexemeStatementEntityReferenceExtractor.