replace network_confirm scripts with one request mirror script

[jakoch]

We can remove some lines of code by de-duplicating the network_confirm.php code.
My suggestion is to use one central script for request mirroring.
The idea is to build a JSON response and use array/object access in tests.
(Basically a note for myself, before the idea gets lost.)
Quick draft:

$url = 'http://';
if (isset($_SERVER['HTTPS'])) {
    $url = 'https://';
}
$url .= "{$_SERVER['HTTP_HOST']}{$_SERVER['PHP_SELF']}";
if ($_SERVER['QUERY_STRING']) {
    $url .= "?{$_SERVER['QUERY_STRING']}";
}
$request = array(
    'body' => file_get_contents('php://input'),
    'headers' => getallheaders(),
    'origin' => $_SERVER['REMOTE_ADDR'],
    'method' => $_SERVER['REQUEST_METHOD'],
    'params' => array(
        'get' => $_GET,
        'post' => $_POST,
    ),
    'url' => $url,
);
header('Content-Type: application/json');
echo json_encode($request);