- Moved the description for the specific storage exception first

- Introduced exceptions for try to get invalid storage
- ReferenceStorageException now extends StorageException

src/Model/Storage/ReferenceStorageException.php

@@ -21,11 +21,9 @@
 
 namespace Friendica\Model\Storage;
 
-use Exception;
-
 /**
  * Storage Exception in case of invalid references
  */
-class ReferenceStorageException extends Exception
+class ReferenceStorageException extends StorageException
 {
 }