Report ARC connectivity diagnostics separately for ipv4 and ipv6

[Wade_Oram]

I expanded a bit on the way in which separate IPv4 and IPv6 connectivity may be reported in my post at:

ARC connectivity improvements, Roon Build 1407/ARC 266

My feeling is slightly different: I think the current “Ready”/“Not Ready” status indicator can have an extra two values added that would only be used when IPv6 was configured on the Roon Server. Note: In the description below, I have used “IPv4 Ready” and “IPv6 Ready” to emphasise the positives but you could use values that complety describe the situation (“IPv4 Ready, IPv6 Not Ready”, “IPv6 Ready, IPv4 Not Ready”) or emphasise the IPv4 state (“IPv4 Ready”, “IPV4 Not Ready”) if these were pref…