Pull request: refactor-opts

Updates #2893.

Squashed commit of the following:

commit c7027abd1088e27569367f3450e9225ff605b43d
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Oct 5 16:54:23 2022 +0300

    home: imp docs

commit 86a5b0aca916a7db608eba8263ecdc6ca79c8043
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Oct 5 16:50:44 2022 +0300

    home: refactor opts more

commit 74c5989d1edf8d007dec847f4aaa0d7a0d24dc38
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Oct 5 15:17:26 2022 +0300

    home: refactor option parsing

internal/home/auth_test.go

@@ -12,16 +12,11 @@ import (
 	"testing"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
 	"github.com/AdguardTeam/golibs/testutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
-func TestMain(m *testing.M) {
-	aghtest.DiscardLogOutput(m)
-}
-
 func TestNewSessionToken(t *testing.T) {
 	// Successful case.
 	token, err := newSessionToken()