[mdns] - fix service resolving when using mdns-embedded
- don't call our dnsresolver in the callback but try it in the zeroconf thread instead
- if that fails (as it does in some networks/platforms where gethostbyname doesn't resolve .local. domains) - fallback to the mdns resolver
[mdns] - enable zeroconfbrowser via mdnsembedded - as the browsing/service-resolveing issue is solved now