[CLA] add signature for FrancescoBallerini

Part-of: odoo/odoo#117435

doc/cla/individual/francescoballerini.md

+Italy, 2023-04-02
+
+I hereby agree to the terms of the Odoo Individual Contributor License Agreement v1.0.
+
+I declare that I am authorized and able to make this agreement and sign this declaration.
+
+Signed,
+
+Francesco Ballerini francescobl.lavoro@gmail.com https://github.com/FrancescoBallerini