Endpoint Manager support for Yealink's T7X and T8X lineup

@mwhite mentioned back in October, that some brands/models were being added. Mike, do you have any updates you can share? https://community.freepbx.org/t/alcatel-m7-with-endpoint-manager/107967/2

I have several districts that have expressed interest in leaving Call Manager(Newer Cisco Phones) and Mitel systems if their existing hardware can be used.

Thanks,

Taylor