Get router ports from PaloAlto firewalls

[lunkwill42]

Is your feature request related to a problem? Please describe.

#2613 added the initial ability for NAV to get ARP data from PaloAlto firewalls using the firewall's REST API. These firewalls, although they support SNMP, do not support the required MIBs to provide ARP cache data over SNMP.

It turns out, these firewalls will also not provide information about their IP address through IP-MIB or known equivalents, meaning NAV is unable to identify any of the firewall's interfaces as router ports.

Describe the solution you'd like

NAV should identify router ports and their IP addresses using the same REST API as the paloaltoarp plugin has already implemented.

Additional context

This feature should of course re-use the HTTP API management profiles that were added for PaloAlto.