Documentation: Add programming guide section on physics engines

[pushfoo]

Documentation request:

What documentation needs to be added?

A high-level overview of how to work with physics engines such as PyMunk, making sure to warn users about the engine overwriting angle, position, and other attributes after calling physics_engine.step()

Where should it be added?

A physics engine page in the programming guide.

Details

I had an issue with PyMunk in the past where attempting to teleport a sprite by changing the position did not work, and a user asked a similar question in the help channels yesterday about why setting the angle wasn't working.

This is a recurring issue, so it makes sense to include a warning about this and other physics engine pitfalls in the programming guide.

[pushfoo]

TL;DR: I can rough this from notes and docstrings, then have @DragonMoffon review

The plan:

1. Get Fix incorrect PhyicsEnginePymunk doc and expand some stubs #2216 merged
2. Do follow-up passes with Dragon
3. Move things we find excessive to this new page
4. Make sure we cover the sync issue:
   • Briefly in the tutorial
   • Thoroughly in this page
   • Cross-referenced by the tut and API doc