Some much needed refactoring

[thecodrr]

Why:

The current codebase is all over the place. It lacks consistency, is hard to navigate and the amount of things being passed around in function calls is absurd. As such, contributing is a nightmare.

After this much needed refactoring, hopefully, it will be more readable and maintainable.

Goals:

• [x] No breaking changes
• [x] Consistent function, variable & parameter naming
• [x] Good internal function commenting
• [x] Write ARCHITECTURE.md
• [x] Write CONTRIBUTING.md
• [x] Simplify function signatures as much as possible
• [x] No performance regressions
• [x] (Optional) Reduce as many closures as possible

[papb]

Nice work!!

[thecodrr]

Thanks! @papb