Refactor and bug fix

[Rudxain]

• Fixed unresolved import (commit link)
• Added helpers.py for easier code sharing between modules
• Convert magic numbers/strings into enums to get the benefits from vars and dicts
• Added more type annotations for static type checking
• Added Final annotations to avoid accidental assignment of immutable vars (also to reduce cognitive load of managing global vars)
• Added and edited comments (regular and docs)
• Make 0Byte programs valid (doesn't work with crickroll)
• etc...

Disclaimer: I tested most (not all) of the changes

[SatinWukerORIG]

Wow those are a lot of changes.

[Rudxain]

Wow those are a lot of changes.

Yeah lol. I'm almost done (I guess). Don't worry, I'll try to keep the diff small (for easier review)

[Rudxain]

I realized using a keyword dictionary instead of an enum is a bad idea, because it doesn't have the benefits of vars. IDEs can easily catch enum typos, but not dict-key typos, and it also allows for auto-completion

[SatinWukerORIG]

You are right lol. I did not put effort in code optimization, sorry for causing this inconvenience. Thank you for making these changes, I appreciate your hard work!

[SatinWukerORIG]

Yes, it is better if you finish everything in one PR lol, and after this change, I will merge it.

[Rudxain]

Ok lol. I'm gonna speedrun this! (it's a joke, don't worry lol, I'll take my time to avoid more mistakes)

[Rudxain]

@SatinWuker it's ready! Please give me feedback, there might be places where it may be better to revert changes (like making a type annotation less verbose, or formatting in a different way, etc...). There may be bugs/mistakes, but I "triple-checked", so it's unlikely, lol

[SatinWukerORIG]

Thank you! Those are some huge changes lol, I am merging it.