[enhancement] Improve list of known devices using FortiManager CLI

[diggedypomme]

Heya I was just looking at something similar for myself, and I noted that if you have access to a Fortimanager, and you run
'diagnose dvm supported-platforms list'
in the cli it will output a large list of devices with their corresponding alias (starting prefix). It's just going to be ones relevant to that version of Fortimanager, but it's a large list.

Kind regards

[p0dalirius]

This is interesting but I don't have access to a FortiManager yet, I'll leave this issue open for now