cherry-pick: 2875 client settings

Merge in DNS/adguard-home from 2875-client-settings to master

Updates #2875.

Squashed commit of the following:

commit 43e5af66acb8ace71a329fe2effae6a78492d73f
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Wed May 12 18:12:03 2021 +0300

    all: fix client settings applying

internal/dnsforward/dnsforward.go

@@ -370,9 +370,7 @@ func (s *Server) setupResolvers(localAddrs []string) (err error) {
 	// really applicable here since in case of listening on all network
 	// interfaces we should check the whole interface's network to cut off
 	// all the loopback addresses as well.
-	localAddrs = aghstrings.FilterOut(localAddrs, func(s string) (ok bool) {
-		return ourAddrsSet.Has(s)
-	})
+	localAddrs = aghstrings.FilterOut(localAddrs, ourAddrsSet.Has)
 
 	var upsConfig proxy.UpstreamConfig
 	upsConfig, err = proxy.ParseUpstreamsConfig(localAddrs, upstream.Options{

internal/dnsforward/filter.go

@@ -50,8 +50,6 @@ func (s *Server) getClientRequestFilteringSettings(ctx *dnsContext) *dnsfilter.F
 // filtered.
 func (s *Server) filterDNSRequest(ctx *dnsContext) (*dnsfilter.Result, error) {
 	d := ctx.proxyCtx
-	// TODO(e.burkov): Consistently use req instead of d.Req since it is
-	// declared.
 	req := d.Req
 	host := strings.TrimSuffix(req.Question[0].Name, ".")
 	res, err := s.dnsFilter.CheckHost(host, req.Question[0].Qtype, ctx.setts)