⚠️ Fix most animations/transitions performance issues

- Basically add `will-change` to CSS elements to enable GPU animations, less choppy, more sassy
- Use requestAnimationFrame over setTimeout
- Avoid repaints AMAP

src/utils/Transition.svelte

@@ -29,7 +29,7 @@
             // Scroll to page top
             window.scrollTo(0,0)
             // Run the page animation / after a tiny delay
-            setTimeout(() => animateIn(scope), 1)
+            requestAnimationFrame(() => animateIn(scope))
         }, animDelayPanel)
     })
 </script>