Scene in memory persistance and debug tools (#24)

![image](https://github.com/storytold/storyteller-bevy/assets/10954133/10eb5c33-2154-4e9d-95ce-1d8e8b822d22)
Debug tools example

---------

Co-authored-by: Danny McGee <dannymcgee@gmail.com>

studio/src/camera_controller.rs

@@ -179,6 +179,8 @@ fn process_focus_inputs(
             // Zero out any existing camera velocity or interpolation
             **velocity = Vec3::ZERO;
 
+            info!("Setting focus to {:?}", target);
+
             if q_interp_vel.get(ent).is_ok() {
                 cmd.entity(ent).remove::<InterpVelocity>();
             }