bevy_render: Centralize shader View uniform type

[superdump]

Objective

• Keep the shader-side definition of the ViewUniform struct in one place, in bevy_render
• The long-term fix from [Merged by Bors] - Fix View by adding missing fields present in ViewUniform #5512 and [Merged by Bors] - Sync up bevy_sprite and bevy_ui shader View struct #5531

Solution

• Move shader View struct to a shader import at bevy_render::view_types
• Make shader view bindings for binding the view uniform to group 0 binding 0 as this is very common, at bevy_render::view_bindings - note that this itself imports bevy_render::view_types for convenience as we have done elsewhere
• Remove the shader View struct from mesh_view_types.wgsl in bevy_pbr, mesh2d_view_types.wgsl and sprite.wgsl in bevy_sprite and ui.wgsl in bevy_ui and instead make use of the above imports.

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Changelog

• Removed: bevy_sprite::mesh2d_view_types and bevy_sprite::mesh2d_view_bindings
• Added: bevy_render::view_types and bevy_render::view_bindings
• Changed: All of bevy_pbr, bevy_sprite, and bevy_ui now use bevy_render::view_types and bevy_render::view_bindings to keep the shader View struct in-sync

Migration Guide

If you were using the bevy_sprite::mesh2d_view_types and/or bevy_sprite::mesh2d_view_bindings shader imports, now use bevy_render::view_types and/or bevy_render::view_bindings instead.

[superdump]

I tested lighting, mesh2d, many_sprites, and ui and all look ok to me.

[nicopap]

Is this still relevant? Kind of a nice small change

[superdump]

I forgot that this was never merged. Definitely something we want to do in my opinion because of how ViewUniform is reused.

[cart]

We have centralized the View type under bevy_render::view. With the new import system, it looks like #import bevy_render::view View. However binding imports are still separated inside bevy_pbr::mesh_view_bindings and bevy_sprite::mesh2d_view_bindings.

I like the idea of standardizing the view binding position and consolidating the import under bevy_render. We might also want to standardize the globals binding position to group(0) binding(1) and also place it in bevy_render?

[richchurcher]

Backlog cleanup: hasn't seen any activity in awhile, migrating to issue #15645 as likely to still be useful.