Resolve #3482394: "Move components from topbar to sidebar"

Closes #3482394

This MR:

• Moves the components and section menu to the primary panel under the Library tab
• The Library tab is now managed by redux in primaryPanelSlice.ts so the 'Add section' and 'Add component' functionality still works.
• Components accordion dropdown is open as the initial state (choice I made)
• Renamed PrimaryMenu.tsx -> PrimaryPanel.tsx to be consistent with ContextualPanel.
• Renamed addMenuSlice.ts -> primaryPanelSlice.ts
• Commented out old AddMenu code (files in /topbar/add/) with a todo comment at the top to reuse when the modules menu work happens.
• Renamed the enum NodeType -> LayoutItemType ('component' | 'section') in primaryPanelSlice.ts to avoid confusion with the LayoutNode enum ('slot' | 'component' | 'root') in layoutModelSlice.ts
• Added scrolling to PrimaryPanel

ui/src/app/App.tsx

@@ -3,7 +3,7 @@ import Layout from '@/features/layout/Layout';
 import { Outlet } from 'react-router-dom';
 import Canvas from '@/features/canvas/Canvas';
 import ErrorBoundary from '@/components/error/ErrorBoundary';
-import PrimaryMenu from '@/components/sidebar/PrimaryMenu';
+import PrimaryPanel from '@/components/sidebar/PrimaryPanel';
 import Topbar from '@/components/topbar/Topbar';
 import useSyncComponentId from '@/hooks/useSyncComponentId';
 import ZoomControl from '@/components/zoom/ZoomControl';
@@ -23,7 +23,7 @@ const App: React.FC = () => {
           <Layout />
         </ErrorBoundary>
         <Topbar />
-        <PrimaryMenu />
+        <PrimaryPanel />
         <Outlet />
         <ZoomControl />
         <div id="menuBarContainer"></div>