Refactor Helper.ts

[andersfischernielsen]

Move non-shared functions to corresponding rules, rename DiceRollType

• All the functions in Helper.ts have been moved to the rule the were only used from
• Some nearly identical functions were refactored to avoid repetition
• DiceRollType has been renamed to DiceRoll, leading to client changes
• WARN has been added as a warning for comments (we shouldn't have "//WARN" lying around)
• Tests have been changed according to refactor