Add and optimize type hints, refactor functions, improve readability

Various changes have been made in the codebase to improve readability and maintainability. Type hints have been added to the functions and variables for better understanding of the datatypes. Refactoring of some code segments has also been done to make the code more concise and readable. The 'EffectType', 'ItemType' enumerations have been enriched with docstrings for better understanding of the enums. Certain classes have been updated to better follow the single responsibility principle.