New API-driven architecture

internal/handler/web/js/install.js

@@ -0,0 +1,9 @@
+function install() {
+    document.title = "安装程序 - MeowBox";
+    const container = document.createElement('div');
+    container.classList.add('container');
+    document.body.appendChild(container);
+}
+document.addEventListener('DOMContentLoaded', () => {
+    install();
+});