Pull request: Migrate to netip.Addr vol.1

Merge in DNS/adguard-home from 2926-lla-v6 to master

Updates #2926.
Updates #5035.

Squashed commit of the following:

commit 2e770d4b6d4e1ec3f7762f2f2466662983bf146c
Merge: 25c1afc5 893358ea
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Oct 14 15:14:56 2022 +0300

    Merge branch 'master' into 2926-lla-v6

commit 25c1afc5f0a5027fafac9dee77618886aefee29c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Thu Oct 13 18:24:20 2022 +0300

    all: imp code, docs

commit 59549c4f74ee17b10eae542d1f1828d4e59894c9
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Oct 11 18:49:09 2022 +0300

    dhcpd: use netip initially

commit 1af623096b0517d07752385540f2f750f7f5b3bb
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Sep 30 18:03:52 2022 +0300

    all: imp docs, code

commit e9faeb71dbc0e887b25a7f3d5b33a401805f2ae7
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Thu Sep 29 14:56:37 2022 +0300

    all: use netip for web

commit 38305e555a6884c3bd1b0839330b942ce0e59093
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Sep 28 19:13:58 2022 +0300

    add basic lla

internal/home/web.go

@@ -4,8 +4,8 @@ import (
 	"context"
 	"crypto/tls"
 	"io/fs"
-	"net"
 	"net/http"
+	"net/netip"
 	"sync"
 	"time"
 
@@ -37,7 +37,7 @@ type webConfig struct {
 	clientFS     fs.FS
 	clientBetaFS fs.FS
 
-	BindHost     net.IP
+	BindHost     netip.Addr
 	BindPort     int
 	BetaBindPort int
 	PortHTTPS    int
@@ -135,8 +135,11 @@ func newWeb(conf *webConfig) (w *Web) {
 //
 // TODO(a.garipov): Adapt for HTTP/3.
 func webCheckPortAvailable(port int) (ok bool) {
-	return Context.web.httpsServer.server != nil ||
-		aghnet.CheckPort("tcp", config.BindHost, port) == nil
+	if Context.web.httpsServer.server != nil {
+		return true
+	}
+
+	return aghnet.CheckPort("tcp", netip.AddrPortFrom(config.BindHost, uint16(port))) == nil
 }
 
 // TLSConfigChanged updates the TLS configuration and restarts the HTTPS server