What is says on the tin.
This has got more to do with making `clippy` slightly more *quiet* than it does with changing anything that might greatly impact readability or performance.
that said, deriving `Default` for a couple of structs is a nice easy win
# Objective
The documentation was unclear but it seemed like it was intended to _only_ flip the texture coordinates of the quad. However, it was also swapping the vertex positions, which resulted in inverted winding order so the front became a back face, and the normal was pointing into the face instead of out of it.
## Solution
- This change makes the only difference the UVs being horizontally flipped.
This makes the [New Bevy Renderer](#2535) the default (and only) renderer. The new renderer isn't _quite_ ready for the final release yet, but I want as many people as possible to start testing it so we can identify bugs and address feedback prior to release.
The examples are all ported over and operational with a few exceptions:
* I removed a good portion of the examples in the `shader` folder. We still have some work to do in order to make these examples possible / ergonomic / worthwhile: #3120 and "high level shader material plugins" are the big ones. This is a temporary measure.
* Temporarily removed the multiple_windows example: doing this properly in the new renderer will require the upcoming "render targets" changes. Same goes for the render_to_texture example.
* Removed z_sort_debug: entity visibility sort info is no longer available in app logic. we could do this on the "render app" side, but i dont consider it a priority.
it's a followup of #1550
I think calling explicit methods/values instead of default makes the code easier to read: "what is `Quat::default()`" vs "Oh, it's `Quat::IDENTITY`"
`Transform::identity()` and `GlobalTransform::identity()` can also be consts and I replaced the calls to their `default()` impl with `identity()`
