feat: reduce the amount of duplicate work the broad-phase is doing for user changes and CCD + release v0.28.0 (#872)

* feat: reduce the amount of duplicate work the broad-phase is doing for user changes and CCD

* Release v0.28.0

* chore: fix warnings

* chore: clippy fixes

* chore: more clippy fixes

examples3d/debug_balls3.rs

@@ -0,0 +1,59 @@
+use rapier_testbed3d::Testbed;
+use rapier3d::prelude::*;
+
+pub fn init_world(testbed: &mut Testbed) {
+    /*
+     * World
+     */
+    let mut bodies = RigidBodySet::new();
+    let mut colliders = ColliderSet::new();
+    let impulse_joints = ImpulseJointSet::new();
+    let multibody_joints = MultibodyJointSet::new();
+
+    /*
+     * Create the balls
+     */
+    let num_j = 10;
+    let num_ik = 10;
+    let rad = 0.5;
+
+    let shift = rad * 2.0;
+    let centerx = shift * (num_ik as f32) / 2.0;
+    let centery = shift / 2.0;
+    let centerz = shift * (num_ik as f32) / 2.0;
+
+    for i in 0..num_ik {
+        for j in 0usize..num_j {
+            for k in 0..num_ik {
+                let x = i as f32 * shift - centerx;
+                let z = k as f32 * shift - centerz;
+
+                let status = if j == 0 || i == 0 || k == 0 || i == num_ik - 1 || k == num_ik - 1 {
+                    RigidBodyType::Fixed
+                } else {
+                    RigidBodyType::Dynamic
+                };
+
+                let y = if status.is_fixed() {
+                    j as f32 * shift + centery
+                } else {
+                    j as f32 * shift * 2.0 + centery
+                };
+
+                // Build the rigid body.
+                let rigid_body = RigidBodyBuilder::new(status)
+                    .translation(vector![x, y, z])
+                    .can_sleep(false);
+                let handle = bodies.insert(rigid_body);
+                let collider = ColliderBuilder::ball(rad).friction(0.0);
+                colliders.insert_with_parent(collider, handle, &mut bodies);
+            }
+        }
+    }
+
+    /*
+     * Set up the testbed.
+     */
+    testbed.set_world(bodies, colliders, impulse_joints, multibody_joints);
+    testbed.look_at(point![100.0, 100.0, 100.0], Point::origin());
+}