Pull request: replace agherr with golibs' errors

Merge in DNS/adguard-home from golibs-errors to master

Squashed commit of the following:

commit 5aba278a31c5a213bd9e08273ce7277c57713b22
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon May 24 17:05:18 2021 +0300

    all: imp code

commit f447eb875b81779fa9e391d98c31c1eeba7ef323
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon May 24 15:33:45 2021 +0300

    replace agherr with golibs' errors

internal/home/controlinstall.go

@@ -15,7 +15,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
 	"github.com/AdguardTeam/golibs/log"
 )
@@ -271,7 +270,7 @@ func copyInstallSettings(dst, src *configuration) {
 const shutdownTimeout = 5 * time.Second
 
 func shutdownSrv(ctx context.Context, cancel context.CancelFunc, srv *http.Server) {
-	defer agherr.LogPanic("")
+	defer log.OnPanic("")
 
 	if srv == nil {
 		return