Remove IIFEs around several javascript classes

What does this MR do?

Reduces ~"technical debt" by removing needless IIFEs wrapping several classes.

This MR merely changes indentation, removes wrapper functions, and occasionally changes variable names which were previously translated via IIFE parameters. It should be straight forward to review.

Are there points in the code the reviewer needs to double check?

All tests should pass.

Why was this MR needed?

Before we can really start code splitting, we need a good dependency graph that doesn't rely on global variables, and before we can factor out globals into proper ES module exports we must remove these IIFEs.

Screenshots (if relevant)

n/a

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

related to #29219 (moved)