refactor(web_server.py): render login.html instead of bare form in /login

judas_server/web/web_server.py

@@ -75,12 +75,7 @@ def login() -> str:
             return flask.redirect(flask.url_for("panel"))
         else:
             return "Invalid password", 401
-    return """
-        <form method="post">
-            Password: <input type="password" name="password">
-            <input type="submit" value="Login">
-        </form>
-    """
+    return flask.render_template("login.html")
 
 
 @app.route("/logout")