Confirm strongly typed inheritance use case

Generated class may have a super type which is a baseType of the DMN type. Firstly, I think I should fix the order of this logic (call ucFirst() at last).

https://github.com/kiegroup/drools/blob/master/kie-dmn/kie-dmn-core/src/main/java/org/kie/dmn/typesafe/DMNDeclaredType.java#L86-L87

However, I'm not able to write a meaningful test case because DMN type may have baseType but it results in the same structure (other than collection). See tEmployee in inheritType.dmn

If we want to allow Employee class to extends Person class, we will need some more fixes in class generation (currently, Employee has its own fields like name, age. Make super class fields protected? or access super class's fields with getter?)