frontend-app-api: extract createApp out into frontend-defaults

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

docs/frontend-system/architecture/10-app.md

@@ -16,7 +16,7 @@ Below is a simple example of how to create and render an app instance:
 
 ```ts
 import ReactDOM from 'react-dom/client';
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 
 // Create your app instance
 const app = createApp({

docs/frontend-system/architecture/25-extension-overrides.md

@@ -295,7 +295,7 @@ export default createExtensionOverrides({
 Assuming the above code resides in the `@internal/search-page` package, you can install it in your app like this:
 
 ```tsx title="packages/app/src/App.tsx"
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 import searchPageOverride from '@internal/search-page';
 
 const app = createApp({

docs/frontend-system/architecture/36-routes.md

@@ -256,7 +256,7 @@ app:
 We also have the ability to express this in code as an option to `createApp`, but you of course only need to use one of these two methods:
 
 ```tsx title="packages/app/src/App.tsx"
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 import catalog from '@backstage/plugin-catalog';
 import scaffolder from '@backstage/plugin-scaffolder';
 

docs/frontend-system/building-apps/01-index.md

@@ -30,13 +30,13 @@ The created-app is currently templated for legacy frontend system applications,
 
 ## The app instance
 
-The starting point of a frontend app is the `createApp` function, which accepts a single options object as its only parameter. It is imported from `@backstage/frontend-app-api`, which is where you will find most of the common APIs for building apps.
+The starting point of a frontend app is the `createApp` function, which accepts a single options object as its only parameter. It is imported from `@backstage/frontend-defaults`, which is where you will find most of the common APIs for building apps.
 
 This is how to create a minimal app:
 
 ```tsx title="in src/index.ts"
 import ReactDOM from 'react-dom/client';
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 import catalogPlugin from '@backstage/plugin-catalog/alpha';
 
 // Create your app instance
@@ -87,7 +87,7 @@ Previously you would customize the application routes, components, apis, sidebar
 A manual installation is required if your packages are not discovered automatically, either because you are not using `@backstage/cli` to build your application or because the features are defined in local modules in the app package. In order to manually install a feature, you must import it and pass it to the `createApp` function:
 
 ```tsx title="packages/app/src/App.tsx"
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 // This plugin was create as a local module in the app
 import { somePlugin } from './plugins';
 
@@ -104,10 +104,10 @@ You can also pass overrides to the features array, for more details, please read
 
 ### Using an async features loader
 
-In case you need to perform asynchronous operations before passing features to the `createApp` function, define a [feature loader](https://backstage.io/docs/reference/frontend-app-api.createappfeatureloader/) object and pass it to the `features` option:
+In case you need to perform asynchronous operations before passing features to the `createApp` function, define a [feature loader](https://backstage.io/docs/reference/frontend-defaults.createappfeatureloader/) object and pass it to the `features` option:
 
 ```tsx title="packages/app/src/App.tsx"
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 
 const app = createApp({
   features: {
@@ -129,7 +129,7 @@ export default app.createRoot();
 In some cases we want to load our configuration from a backend server and to do so, you can pass an callback to the `configLoader` option when calling the `createApp` function, the callback should return a promise of an object with the config object:
 
 ```tsx title="packages/app/src/App.tsx"
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 import { getConfigFromServer } from './utils';
 
 // Example lazy loading the app configuration

docs/frontend-system/building-apps/08-migrating.md

@@ -18,7 +18,7 @@ The first step in migrating an app is to switch out the `createApp` function for
 // highlight-remove-next-line
 import { createApp } from '@backstage/app-defaults';
 // highlight-add-next-line
-import { createApp } from '@backstage/frontend-app-api';
+import { createApp } from '@backstage/frontend-defaults';
 ```
 
 This immediate switch will lead to a lot of breakages that we need to fix.