Add AppMetadata API

- Load base app medata
- Optionally pre-load module metadata
- Add module metadata api
-- Load base module metadata
-- Load recently viewed

core/backend/Themes/Entity/ThemeImages.php

@@ -100,4 +100,16 @@ class ThemeImages
 
         return $this;
     }
+
+    /**
+     * @return array
+     */
+    public function toArray(): array
+    {
+        return [
+            'id' => $this->getId(),
+            '_id' => $this->getId(),
+            'items' => $this->getItems(),
+        ];
+    }
 }