Make Resource trait opt-in, requiring #[derive(Resource)] V2 (#5577)

*This PR description is an edited copy of #5007, written by @alice-i-cecile.*
# Objective
Follow-up to bevyengine/bevy#2254. The `Resource` trait currently has a blanket implementation for all types that meet its bounds.

While ergonomic, this results in several drawbacks:

* it is possible to make confusing, silent mistakes such as inserting a function pointer (Foo) rather than a value (Foo::Bar) as a resource
* it is challenging to discover if a type is intended to be used as a resource
* we cannot later add customization options (see the [RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/27-derive-component.md) for the equivalent choice for Component).
* dependencies can use the same Rust type as a resource in invisibly conflicting ways
* raw Rust types used as resources cannot preserve privacy appropriately, as anyone able to access that type can read and write to internal values
* we cannot capture a definitive list of possible resources to display to users in an editor
## Notes to reviewers
 * Review this commit-by-commit; there's effectively no back-tracking and there's a lot of churn in some of these commits.
   *ira: My commits are not as well organized :')*
 * I've relaxed the bound on Local to Send + Sync + 'static: I don't think these concerns apply there, so this can keep things simple. Storing e.g. a u32 in a Local is fine, because there's a variable name attached explaining what it does.
 * I think this is a bad place for the Resource trait to live, but I've left it in place to make reviewing easier. IMO that's best tackled with bevyengine/bevy#4981.

## Changelog
`Resource` is no longer automatically implemented for all matching types. Instead, use the new `#[derive(Resource)]` macro.

## Migration Guide
Add `#[derive(Resource)]` to all types you are using as a resource.

If you are using a third party type as a resource, wrap it in a tuple struct to bypass orphan rules. Consider deriving `Deref` and `DerefMut` to improve ergonomics.

`ClearColor` no longer implements `Component`. Using `ClearColor` as a component in 0.8 did nothing.
Use the `ClearColorConfig` in the `Camera3d` and `Camera2d` components instead.


Co-authored-by: Alice <[email protected]>
Co-authored-by: Alice Cecile <[email protected]>
Co-authored-by: devil-ira <[email protected]>
Co-authored-by: Carter Anderson <[email protected]>

Author: 3 people

src/lib.rs

@@ -316,7 +316,7 @@ impl Default for WinitPersistentState {
     }
 }
 
-#[derive(Default)]
+#[derive(Default, Resource)]
 struct WinitCreateWindowReader(ManualEventReader<CreateWindow>);
 
 pub fn winit_runner_with(mut app: App) {

src/web_resize.rs

@@ -20,13 +20,14 @@ struct ResizeEvent {
     window_id: WindowId,
 }
 
+#[derive(Resource)]
 pub(crate) struct CanvasParentResizeEventChannel {
     sender: Sender<ResizeEvent>,
     receiver: Receiver<ResizeEvent>,
 }
 
 fn canvas_parent_resize_event_handler(
-    winit_windows: Res<WinitWindows>,
+    winit_windows: NonSend<WinitWindows>,
     resize_events: Res<CanvasParentResizeEventChannel>,
 ) {
     for event in resize_events.receiver.try_iter() {

src/winit_config.rs

@@ -1,7 +1,8 @@
+use bevy_ecs::system::Resource;
 use bevy_utils::Duration;
 
 /// A resource for configuring usage of the `rust_winit` library.
-#[derive(Debug)]
+#[derive(Debug, Resource)]
 pub struct WinitSettings {
     /// Configures the winit library to return control to the main thread after the
     /// [run](bevy_app::App::run) loop is exited. Winit strongly recommends avoiding this when