Pull request: all: simplify dnssec logic

Closes #3904.

Squashed commit of the following:

commit 5948f0d3519299a1253e388f4bc83e2e55847f68
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 13 17:53:40 2021 +0300

    querylog: imp

commit 852cc7dbdb495a17ff51b99ab12901b846f8be09
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 13 17:44:41 2021 +0300

    querylog: fix entry write

commit 9d58046899f35162596bfc94fe88fa944309b2fd
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 13 16:45:56 2021 +0300

    all: simplify dnssec logic

internal/dnsforward/stats_test.go

@@ -22,11 +22,11 @@ type testQueryLog struct {
 	// a querylog.QueryLog without actually implementing all methods.
 	querylog.QueryLog
 
-	lastParams querylog.AddParams
+	lastParams *querylog.AddParams
 }
 
 // Add implements the querylog.QueryLog interface for *testQueryLog.
-func (l *testQueryLog) Add(p querylog.AddParams) {
+func (l *testQueryLog) Add(p *querylog.AddParams) {
 	l.lastParams = p
 }