Mass mailing restrictions

• Remove mass mailing user permission from all roles except from platform admin
• Restrict menu root visibility for mass_mailing users

Fixes: https://trello.com/c/HZDdW5I9/385-desactivar-acc%C3%A9s-al-m%C3%B2dul-de-massmailing-per-qualsevol-role-diferent-de-platformadmin

energy_communities/views/mailing_mailing_views_menus.xml

+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+  <data>
+    <record model="ir.ui.menu" id="mass_mailing.mass_mailing_menu_root">
+      <field
+        name="groups_id"
+        eval="[(6,0,[ref('mass_mailing.group_mass_mailing_user')])]"
+      />
+    </record>
+  </data>
+</odoo>