Expand the sections regarding Jitter, Stutter and Latency

[darksylinc]

This guide has basically two parts:

1. The result of thorough examination of all the problems found that were not caused by Godot (but were attributed to it). This adds an in-depth guide on how to locate and fix such issues.
2. A guide to the new code introduced by PR https://github.com/godotengine/godot/pull/106221 which still needs to be merged.

This is my first PR to godot-docs so please point out if I made a mistake and I apologize any mistake that could've been solved with a RTFM (I did read it, but I probably missed something).