Implement user management

Implement dark mode for UI

frontend/scripts/prefers-color-scheme.js

@@ -0,0 +1,12 @@
+window.applyTheme = () => {
+    const theme = window.matchMedia("(prefers-color-scheme: dark)").matches
+        ? "dark"
+        : "";
+    document.documentElement.setAttribute("theme", theme);
+};
+window
+    .matchMedia("(prefers-color-scheme: dark)")
+    .addEventListener('change', function () {
+        window.applyTheme()
+    });
+window.applyTheme();