Refactor FloppyData property inheritance and defaults

Refactored FloppyData to use Nothing as the default for string and nullable properties, enabling more accurate inheritance from parent objects. Introduced ResolveString, ResolveBoolean, and ResolveNullable helpers to generalize property resolution and reduce code duplication. Updated GetTitleData to use a new GetAttr helper for XML attribute extraction. Improved handling of missing or optional data throughout. Moved DistinctStrings and JoinDistinctStrings for consistency. These changes enhance maintainability and correctness in data modeling.

Author: Digitoxin1