Pull request: 5117-backport-dns64

Merge in DNS/adguard-home from 5117-backport-dns64 to master

Updates #5117.

Squashed commit of the following:

commit 8ac88534b2da52f49facef6d623ea3504a3cd5ed
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Feb 6 16:44:16 2023 +0300

    all: rm todos

commit 0aa66c5ecbadc3e372478ea4446f80fcc7457841
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Feb 6 15:40:38 2023 +0300

    all: upd dnsproxy

commit 872a8efdd2759fd9dad61de9953bc87f734ca918
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Feb 3 14:14:21 2023 +0300

    dnsforward: imp docs

commit 8efeb42cac69bbe9b8dba8c91c33b14c95397ab9
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Feb 1 02:58:01 2023 +0300

    all: rm dns64

internal/dnsforward/config.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"fmt"
 	"net"
+	"net/netip"
 	"os"
 	"sort"
 	"strings"
@@ -225,7 +226,7 @@ type ServerConfig struct {
 	LocalPTRResolvers []string
 
 	// DNS64Prefixes is a slice of NAT64 prefixes to be used for DNS64.
-	DNS64Prefixes []string
+	DNS64Prefixes []netip.Prefix
 
 	// ResolveClients signals if the RDNS should resolve clients' addresses.
 	ResolveClients bool
@@ -271,6 +272,8 @@ func (s *Server) createProxyConfig() (conf proxy.Config, err error) {
 		RequestHandler:         s.handleDNSRequest,
 		EnableEDNSClientSubnet: srvConf.EnableEDNSClientSubnet,
 		MaxGoroutines:          int(srvConf.MaxGoroutines),
+		UseDNS64:               srvConf.UseDNS64,
+		DNS64Prefs:             srvConf.DNS64Prefixes,
 	}
 
 	if srvConf.CacheSize != 0 {