This updates the `pipelined-rendering` branch to use the latest `bevy_ecs` from `main`. This accomplishes a couple of goals:
1. prepares for upcoming `custom-shaders` branch changes, which were what drove many of the recent bevy_ecs changes on `main`
2. prepares for the soon-to-happen merge of `pipelined-rendering` into `main`. By including bevy_ecs changes now, we make that merge simpler / easier to review.
I split this up into 3 commits:
1. **add upstream bevy_ecs**: please don't bother reviewing this content. it has already received thorough review on `main` and is a literal copy/paste of the relevant folders (the old folders were deleted so the directories are literally exactly the same as `main`).
2. **support manual buffer application in stages**: this is used to enable the Extract step. we've already reviewed this once on the `pipelined-rendering` branch, but its worth looking at one more time in the new context of (1).
3. **support manual archetype updates in QueryState**: same situation as (2).
* move print diagnostics to log
* entity count diagnostic
* asset count diagnostic
* remove useless `pub`s
* use `BTreeMap` instead of `HashMap`
* get entity count from world
* keep ordered list of diagnostics
