feat: add dynamic navbar to scenes

Introduced a new CSS file for styling a fixed navbar in scenes,
enhancing user navigation within the virtual environment. Modified
scene.js to include fetching categories and generating a navbar with
scene options dynamically based on the category of the current scene.
This allows users to switch scenes more intuitively. The `nonavbar`
attribute was added for scenes where the navbar should be omitted,
providing flexibility in scene presentation. Additionally, streamlined
CSS and SCSS imports across JS files for consistency and removed an
unnecessary SCSS import from editor.js, optimizing load times and
project structure.

This update significantly improves user experience by facilitating
easier navigation and scene exploration within the application.

assets/js/editor.js

@@ -1,7 +1,6 @@
 import { getScene, getSceneElement, getCategory } from "./api";
 import { populateDestinationDropdown } from "./editor/teleport";
 
-import "../scss/frontend.scss";
 import "../css/editor.css";
 
 let clickTimestamp = 0;