The Game Loop Book Chapter Refresh Tracking Issue

[Based-A]

The Game Loop Book chapter is sorely needing an update, especially compared to other chapters which have been reworked or updated over the last few months. This issue is meant to help organize the content that we want to see place into this chapter.

New Content

Existing Content Updates

• App
  • Expand information and context of what a Bevy App is and can be used for.
    • Render App could be a great example.
• Schedules
  • Expand Fixed schedules explanations & explain where to use them (Add advice/guidance for using FixedUpdate versus Update #2445)
• Time
  • Move Timers and Stopwatch to Control Flow (Split practical time advice/examples into a new Book page #2427)
  • Explain Real, Virtual, Fixed, and Time resources.