Refactor class DctMainCtl by converting its current class variables into instance variables and static methodes to methodes

[SevenOfNinePE]

Refactor the class by converting its current class variables into instance variables. While the existing design uses @staticmethod and class-level attributes, this structure can lead to hidden side effects, reduced clarity, and potential issues with testability and future extensibility. Moreover the @staticmethod methodes shall become normal methodes

Background:
Using instance variables improves encapsulation and allows the class to manage its own state in a clearer, more maintainable way. Even if only one instance is planned, refactoring to instance-based design aligns with object-oriented best practices and paves the way for cleaner design patterns, better readability, and flexibility in potential future modifications.