Moved populateIfNecessary to Neo4jMappingContext from IdPopulator

[akshatbiztech]

I ran DesigniteJava a smell detection tool and detected various smells. I refactored populateIfNecessary based on the "Feature Envy" smell.The tool detected a instance of this smell because populateIfNecessary is more interested in members of the type: Neo4jMappingContext.

Would love to get your feedback on this.

I have attached the file that shows all the design smells.
DesignSmells.csv

[michael-simons]

I don't see any envy or even why this should be a design smell. Your changes ties the that feature now to the mapping context for all time. Which is quite the opposite what you did in #2834. So when using such a tool, you should really think about what the tooling suggest, otherwise you get strange results, very much the same issue with trying test coverage to 100% by testing mutators.