Pull request: home: don't allow all origins

Merge in DNS/adguard-home from 2484-access-control to master

Updates #2484.

Squashed commit of the following:

commit 4f0c6ddae35b55a9251f4d5e14c4d92fd2107443
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Feb 5 12:42:22 2021 +0300

    home: don't allow all origins

internal/home/home_test.go

@@ -133,7 +133,7 @@ func TestHome(t *testing.T) {
 	h := http.Client{}
 	for i := 0; i != 50; i++ {
 		resp, err = h.Get("http://127.0.0.1:3000/")
-		if err == nil && resp.StatusCode != 404 {
+		if err == nil && resp.StatusCode != http.StatusNotFound {
 			break
 		}
 		time.Sleep(100 * time.Millisecond)