Add possibility to allow/disallow main email, email alias and email forward form portal

[Josue-T]

PR related to: YunoHost/yunohost-portal#21

The problem

In Yunohost portal, user is always allowed to edit the mail alias and mail forward rule.

In some instance it could be a security issue to allow to edit by example the mail alias.

Solution

Add 3 new Yunohost settings to define if the user is allowed to edit

• the main email
• the mail alias
• the mail forward

PR Status

Tested locally it work

How to test

• Checkout the branch on yunohost and yunhost-portal
• Allow the 3 rules in "Tools" > "Yunohost settings" > "Portal" from admin
• Test that from the yunohost portal, the user can edit everything.
• Disallow the 3 rules in "Tools" > "Yunohost settings" > "Portal" from admin
• Test that from the yunohost portal, the user can't edit everything.