Include original question in answer

Some mDNS clients (especially on Android) require the question
to be echoed in the answer in order to properly recognise
and process the response.
This change ensures the question is sent back
alongside the answer.

Co-authored-by: atomirex <nige@atomirex.com>

Fix ifcIndex usage in Windows

We were not doing the ifcIndex check correctly which is a bug
everywhere but only shows on Windows right now due to not seeing
Control Messages.

Prefer IPv6 over IPv4-in-IPv6

Improve IPv6 support

This adds Server.QueryAddr for netip.Addr support

Fix incorrect slice addressing

Slice was being filtered but the loop counter wasn't being modified

```
panic: runtime error: index out of range [1] with length 1

goroutine 8 [running]:
        /Users/sean/go/src/github.com/pion/mdns/conn.go:965 +0xb9c
        /Users/sean/go/src/github.com/pion/mdns/conn.go:976 +0x1e4
        /Users/sean/go/src/github.com/pion/mdns/conn.go:1018 +0x90
        /Users/sean/go/src/github.com/pion/mdns/conn.go:1013 +0x234
```

Remove multierr dependency

Keeps the package at 0 dependencies

Relax isSupportedIPv6 to just no mapped

Support dig based unicast requests

e.g. dig -p 5353 @224.0.0.251 pion-test.local

Support IPv6 question and response

- Addresses #69

Use loopback address in responses when configured

Fixes pion/webrtc#2625