feat(container.scss): add container styles for fixed position and scrolling behavior

feat(container.ts): create container module to handle scrollable behavior and add/remove disableScroll class

fix(customCursor.ts): update append target for cursor element to use container instead of main

fix(stage.ts): update append target for stage element to use container instead of main

fix(stageNav.ts): update append target for navOverlay element to use container instead of main

feat(main.ts): initialize container module and conditionally initialize stage and stageNav modules based on device type

fix(nav.ts): update references to state module functions to use state.get() instead of getState()

layouts/index.html

@@ -37,6 +37,6 @@
     <script id="imagesSource" type="application/json">{{ $.Scratch.Get "img" | jsonify | safeJS }}</script>
       {{ end }}
     </div>
-    {{ partial "nav.html" . }}
+    <div class="container">{{ partial "nav.html" . }}</div>
   </body>
 </html>