Add ECSRenderer for improved integration of rendering and ECS

- Introduced ECSRenderer struct to manage the connection between the renderer and the ECS.
- Implemented methods for spawning and despawning meshes within the ECS.
- Updated main function to utilize ECSRenderer for rendering and object management.
- Added a new Time module to handle frame timing and updates.

src/time.rs

@@ -0,0 +1,34 @@
+use std::time::{Duration, Instant};
+
+#[derive(Clone, Debug)]
+pub struct Time {
+    last:   Instant,
+    delta:  Duration,
+    total:  Duration,
+}
+
+impl Time {
+    pub fn new() -> Self {
+        let now = Instant::now();
+        Self {
+            last:  now,
+            delta: Duration::ZERO,
+            total: Duration::ZERO,
+        }
+    }
+
+    pub fn tick(&mut self) {
+        let now = Instant::now();
+        self.delta = now - self.last;
+        self.total += self.delta;
+        self.last = now;
+    }
+
+    pub fn delta_seconds(&self) -> f32 {
+        self.delta.as_secs_f32()
+    }
+
+    pub fn total_seconds(&self) -> f32 {
+        self.total.as_secs_f32()
+    }
+}