chore: add packages config to backend-app-api

Signed-off-by: djamaile <rdjamaile@gmail.com>

.changeset/tricky-ducks-juggle.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-app-api': patch
+---
+
+Add `packages` to backend-app-api configuration schema

packages/backend-app-api/config.d.ts

@@ -287,6 +287,11 @@ export interface Config {
           }
       >;
     };
+    /**
+     * @visibility frontend
+     * @deepVisibility frontend
+     */
+    packages?: 'all' | { include?: string[]; exclude?: string[] };
   };
 
   /** Discovery options. */