Renamed tests
Added test test_prestatechange_to_state_with_post_evaluate_relational
Moved classes into seperated files as CallbackMethodConfigureScanner referencing them
No need to load relation state machine object here

And if we did , infinite loop between configureRelationObject and
configureCallbackObjects will occurred.
Moved unused import
Added imports
Added logic to verify relational preToStatePostEvaluate and evaluateAccessor for mappedBy