cherry-pick: 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()
+}

internal/aghnet/net_darwin.go

@@ -23,10 +23,6 @@ type hardwarePortInfo struct {
 	static    bool
 }
 
-func canBindPrivilegedPorts() (can bool, err error) {
-	return aghos.HaveAdminRights()
-}
-
 func ifaceHasStaticIP(ifaceName string) (bool, error) {
 	portInfo, err := getCurrentHardwarePortInfo(ifaceName)
 	if err != nil {

internal/aghnet/net_freebsd.go

@@ -13,10 +13,6 @@ import (
 	"github.com/AdguardTeam/AdGuardHome/internal/aghos"
 )
 
-func canBindPrivilegedPorts() (can bool, err error) {
-	return aghos.HaveAdminRights()
-}
-
 func ifaceHasStaticIP(ifaceName string) (ok bool, err error) {
 	const rcConfFilename = "etc/rc.conf"
 

internal/aghnet/net_openbsd.go

@@ -13,10 +13,6 @@ import (
 	"github.com/AdguardTeam/AdGuardHome/internal/aghos"
 )
 
-func canBindPrivilegedPorts() (can bool, err error) {
-	return aghos.HaveAdminRights()
-}
-
 func ifaceHasStaticIP(ifaceName string) (ok bool, err error) {
 	filename := fmt.Sprintf("etc/hostname.%s", ifaceName)
 

internal/aghnet/net_windows.go

@@ -1,5 +1,5 @@
-//go:build !(linux || darwin || freebsd || openbsd)
-// +build !linux,!darwin,!freebsd,!openbsd
+//go:build windows
+// +build windows
 
 package aghnet
 
@@ -14,7 +14,7 @@ import (
 )
 
 func canBindPrivilegedPorts() (can bool, err error) {
-	return aghos.HaveAdminRights()
+	return true, nil
 }
 
 func ifaceHasStaticIP(string) (ok bool, err error) {