Move sprite::Rect into bevy_math (bevyengine#5686)

# Objective

Promote the `Rect` utility of `sprite::Rect`, which defines a rectangle
by its minimum and maximum corners, to the `bevy_math` crate to make it
available as a general math type to all crates without the need to
depend on the `bevy_sprite` crate.

Fixes bevyengine#5575

## Solution

Move `sprite::Rect` into `bevy_math` and fix all uses.

Implement `Reflect` for `Rect` directly into the `bevy_reflect` crate by
having `bevy_reflect` depend on `bevy_math`. This looks like a new
dependency, but the `bevy_reflect` was "cheating" for other math types
by directly depending on `glam` to reflect other math types, thereby
giving the illusion that there was no dependency on `bevy_math`. In
practice conceptually Bevy's math types are reflected into the
`bevy_reflect` crate to avoid a dependency of that crate to a "lower
level" utility crate like `bevy_math` (which in turn would make
`bevy_reflect` be a dependency of most other crates, and increase the
risk of circular dependencies). So this change simply formalizes that
dependency in `Cargo.toml`.

The `Rect` struct is also augmented in this change with a collection of
utility methods to improve its usability. A few uses cases are updated
to use those new methods, resulting is more clear and concise syntax.

---

## Changelog

### Changed

- Moved the `sprite::Rect` type into `bevy_math`.

### Added

- Added several utility methods to the `math::Rect` type.

## Migration Guide

The `bevy::sprite::Rect` type moved to the math utility crate as
`bevy::math::Rect`. You should change your imports from `use
bevy::sprite::Rect` to `use bevy::math::Rect`.

crates/bevy_math/Cargo.toml

@@ -10,3 +10,4 @@ keywords = ["bevy"]
 
 [dependencies]
 glam = { version = "0.21", features = ["serde", "bytemuck"] }
+serde = "1"

crates/bevy_math/src/lib.rs

@@ -6,12 +6,16 @@
 
 #![warn(missing_docs)]
 
+mod rect;
+
+pub use rect::Rect;
+
 /// The `bevy_math` prelude.
 pub mod prelude {
     #[doc(hidden)]
     pub use crate::{
-        BVec2, BVec3, BVec4, EulerRot, IVec2, IVec3, IVec4, Mat2, Mat3, Mat4, Quat, UVec2, UVec3,
-        UVec4, Vec2, Vec3, Vec4,
+        BVec2, BVec3, BVec4, EulerRot, IVec2, IVec3, IVec4, Mat2, Mat3, Mat4, Quat, Rect, UVec2,
+        UVec3, UVec4, Vec2, Vec3, Vec4,
     };
 }