use IPv6 scopeid if it's available

[staltz]

Context

IPv6 addresses can have a scope % suffix for example fe80::6d6:aaff:fe87:179c%wlan0 but there are two ways to use that: (1) with the interface name e.g. %wlan0 or (2) a number ID given by the operating system e.g. %4.

The second method is sometimes given by the interface details object, like:

{
  address: 'fe80::f927:7648:edf4:bc96',
  netmask: 'ffff:ffff:ffff:ffff::',
  family: 'IPv6',
  mac: '68:ec:c5:08:d2:ac',
  internal: false,
  cidr: 'fe80::f927:7648:edf4:bc96/64',
  scopeid: 4  // <----------------------------------
}

Problem

The implementation was always adding the scope as the interface name. This could be problematic on Windows where the interface name is something like Local Area Connection so the scope %Local Area Connection wouldn't work.

Solution

Prioritize using details.scopeid if it exists, otherwise fall back to interface name.

Also updates test toolkit and enables tests in CI.

[arj03]

Looks simple enough

[staltz]

Thanks, I also added a test just now.