Create bevy_render_2d crate

[hukasu]

Objective

Work for #18423

Solution

Create bevy_render_2d crate and pull relevant code out of bevy_sprite

Testing

Not enough

Migration Guide

On included file

[github-actions]

You added a new feature but didn't update the readme. Please run cargo run -p build-templated-pages -- update features to update it, and commit the file change.

[IceSentry]

This is a split I want to see, but I'm not sure if we should do it now or wait until 0.16 is released.

[hukasu]

@IceSentry while I was doing this split I was wondering if wireframe should be a crate, it is not really infrastructure for creating materials to be included in bevy_render_2d

The were some changes to system ordering too that needs some verification

[IceSentry]

Yes-ish. All the wireframe material thing is currently broken and needs to be rewritten to use it's own phase. @tychedelia is working on this. Once it's done, then it could be a separate crate, but I think it should probably live in bevy_render for a bit. I don't think wireframes would cause compilation speed issues and if you want to render wireframe you'll need to use bevy_render anyway.

[tychedelia]

Let's definitely wait until after 0.16 and try to get these done expediently as a first task so we don't get stuck in rebase hell. Haven't reviewed the concrete changes yet but thank you for tackling this.

[hukasu]

@tychedelia TLDR: Moved bevy_sprite::mesh2d::mesh.rs and bevy_sprite::mesh2d::material.rs to bevy_render_2d::mesh_pipeline and bevy_render_2d::materials respectively + refactor to my taste