Update and clean up HTML files, upgrade structure

scripts/index.js

@@ -0,0 +1,20 @@
+const redirect = 'https://go.enderman.ch/youtube';
+let video = document.querySelector('#player');
+
+async function sleep(ms) {
+    await new Promise(resolve => setTimeout(resolve, ms));
+}
+
+document.querySelector('.fullscreen').onclick = () => {
+    document.title = 'Downloading...';
+
+    video.style.cursor = 'default';
+    video.play();
+}
+
+video.addEventListener('ended', async () => {
+    document.title = 'Download complete!';
+
+    await sleep(3000);
+    window.location.replace(redirect);
+});