Huge input update, FPS Camera controls system

Long day. I now store winit:🪟:Window in a mutex.

engine/src/system.rs

@@ -5,12 +5,13 @@ use raidillon_platform::PlatformContext;
 use std::any::TypeId;
 use std::cell::RefCell;
 use std::rc::Rc;
+use crate::input::InputState;
 
 pub struct SystemContext<'a> {
-    // TODO: time delta etc.
     pub scene: &'a mut Scene,
     pub platform_context: PlatformContext,
     pub debug_ui_buffer: Rc<RefCell<DebugUIBuffer>>,
+    pub input_state: Rc<RefCell<InputState>>,
 }
 
 pub trait System {