Update DESCRIPTION.md (#622)

Proposition from the Functional Working Group

Co-authored-by: Pedro M. Baeza <pedro.baeza@tecnativa.com>
Co-authored-by: Jairo Llopis <973709+yajo@users.noreply.github.com>

template/module/readme/DESCRIPTION.md

@@ -1,5 +1,7 @@
-[ This file must be max 2-3 paragraphs, and is required. ]
+[ This file must be max 2-3 paragraphs, and is required.
 
-This module extends the functionality of ... to support ...
-and to allow you to ...
+The goal of this document is to explain quickly the features of this module: “what” this module does and “what” it is for. ]
 
+Example:
+
+This module extends the functionality of ... to support ... and to allow users to ...