New SIP Extension/Define SIP Extension

The definition of an extension is comprised of multiple sections.
The most important one is the general one, where you can define the internal number for the extension and the password. The username is automatically generated based on the extension number and the code assigned to the tenant.
Extension number and SIP accounts are tied together. The username format <extension>-<tenant code> is mandatory (see later for exceptions) and cannot be changed.
The number assigned to an extension for a tenant can be the same number assigned to another extension for another tenant.
MiRTA PBX is completely multi tenant, so each tenant configuration is completely independent from others.
This is a general rule applied to every configuration setting.