[ADD] Add base_phone module

[ADD] Add base_phone module;it validates phone numbers using the *phonenumbers* Python library.

This module comes from https://launchpad.net/openerp-asterisk-connector/7.0.

It was done by Alexis de Lattre from Akretion alexis.delattre@akretion.com
Use CamelCase: `PhoneCommon`