feat(techdocs): implement composable home page

Signed-off-by: Phil Kuang <pkuang@factset.com>

packages/create-app/templates/default-app/packages/app/src/App.tsx

@@ -13,7 +13,11 @@ import {
 import { ScaffolderPage, scaffolderPlugin } from '@backstage/plugin-scaffolder';
 import { SearchPage } from '@backstage/plugin-search';
 import { TechRadarPage } from '@backstage/plugin-tech-radar';
-import { TechdocsPage } from '@backstage/plugin-techdocs';
+import {
+  DefaultTechDocsHome,
+  TechDocsIndexPage,
+  TechDocsReaderPage,
+} from '@backstage/plugin-techdocs';
 import { UserSettingsPage } from '@backstage/plugin-user-settings';
 import { apis } from './apis';
 import { entityPage } from './components/catalog/EntityPage';
@@ -50,7 +54,13 @@ const routes = (
     >
       {entityPage}
     </Route>
-    <Route path="/docs" element={<TechdocsPage />} />
+    <Route path="/docs" element={<TechDocsIndexPage />}>
+      <DefaultTechDocsHome />
+    </Route>
+    <Route
+      path="/docs/:namespace/:kind/:name/*"
+      element={<TechDocsReaderPage />}
+    />
     <Route path="/create" element={<ScaffolderPage />} />
     <Route path="/api-docs" element={<ApiExplorerPage />} />
     <Route