Document micro-optimizations that should be done before final game release

## How can Bevy's documentation be improved?

Several performance optimizations can be done just before final release, but are impractical for development.

As a starting point:

- Enabling Link Time Optimization
- Disabling dynamic linking
- Reducing or removing logging, see https://github.com/bevyengine/bevy/pull/4580

These should be documented in a single central place.