Pull request: home: rm unnecessary locking in update; refactor

Merge in DNS/adguard-home from 4499-rm-unnecessary-locking to master

Squashed commit of the following:

commit 6d70472506dd0fd69225454c73d9f7f6a208b76b
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 25 17:26:54 2022 +0300

    home: rm unnecessary locking in update; refactor

internal/aghnet/net_bsd.go

@@ -0,0 +1,10 @@
+//go:build darwin || freebsd || openbsd
+// +build darwin freebsd openbsd
+
+package aghnet
+
+import "github.com/AdguardTeam/AdGuardHome/internal/aghos"
+
+func canBindPrivilegedPorts() (can bool, err error) {
+	return aghos.HaveAdminRights()
+}