feat(create-app): add catalog-info.yaml in the created app (#2759)

* Add template for catalog-info

* Update docs

docs/getting-started/create-an-app.md

@@ -74,6 +74,7 @@ app.
 ```
 app
 ├── app-config.yaml
+├── catalog-info.yaml
 ├── lerna.json
 ├── package.json
 └── packages
@@ -83,6 +84,9 @@ app
 
 - **app-config.yaml**: Main configuration file for the app. See
   [Configuration](https://backstage.io/docs/conf/) for more information.
+- **catalog-info.yaml**: Catalog Entities descriptors. See
+  [Descriptor Format of Catalog Entities](https://backstage.io/docs/features/software-catalog/descriptor-format)
+  to get started.
 - **lerna.json**: Contains information about workspaces and other lerna
   configuration needed for the monorepo setup.
 - **package.json**: Root package.json for the project. _Note: Be sure that you

packages/create-app/templates/default-app/catalog-info.yaml.hbs

@@ -0,0 +1,13 @@
+apiVersion: backstage.io/v1alpha1 
+kind: Component
+metadata:
+  name: {{name}} 
+  description: An example of a Backstage application.
+  # Example for optional annotations
+  # annotations: 
+    # github.com/project-slug: spotify/backstage
+    # backstage.io/techdocs-ref: github:https://github.com/spotify/backstage.git
+spec:
+  type: website
+  owner: john@example.com
+  lifecycle: experimental