我最终实现了我的想法。

我已经在中描述了在站点信息屏幕上创建自定义输入字段的过程this Post. 下面是完整的代码：

<?php
// Create custom Input Field on the WP-Admin > Network > Site Info Screen
// for the possibility to order sites manually 
add_action(\'admin_footer\', \'pg_custom_site_options\');
function pg_custom_site_options(){

    global $pagenow;

    if( \'site-info.php\' == $pagenow ) {

        global $details;

        $blog_id = isset( $_REQUEST[\'id\'] ) ? intval( $_REQUEST[\'id\'] ) : 0;
        if ( ! $blog_id ) wp_die( __(\'Invalid site ID.\') );

        $saved_value = get_blog_option( $blog_id, \'blog_order\');

        ?>
        <table style="display: none;">
            <tr id="user16975_custom_options">
                <th scope="row">Order</th>
                <td><input type="text" size="5" name="blog[blog_order]" value="<?php echo esc_attr( $saved_value ) ?>" ></td>
            </tr>
        </table>
        <script>
            jQuery(function($){
                $(\'.form-table tbody\').append($(\'#user16975_custom_options\'));
            });
        </script>
        <?php

    }
}

add_action(\'admin_init\', \'pg_save_custom_site_options\');
function pg_save_custom_site_options(){

    global $pagenow;

    if( \'site-info.php\' == $pagenow &&
        isset($_REQUEST[\'action\']) &&
        \'update-site\' == $_REQUEST[\'action\']
    ) {
        // Use a default value here if the field was not submitted.
        $new_field_value = \'0\';

        if ( isset( $_POST[\'blog\'][\'blog_order\'] ) ) {
            $new_field_value = intval( $_POST[\'blog\'][\'blog_order\'] );

            // save option into the database
            if( is_int($new_field_value) ){
                update_blog_option( $_POST[\'id\'], \'blog_order\', $new_field_value );
            }

        }

    }
}
?>

$all_standorte =  wp_get_sites( $args );

// Get the order nr of each site and save it in the array
$pos = 0;
foreach( $all_standorte as $standort){

    $standort_id = $standort[\'blog_id\'];

    $blog_order = get_blog_option( $standort_id, \'blog_order\', \'0\');

    $all_standorte[$pos][\'blog_order\'] = $blog_order;

    $pos++;
}

// Sort Sites by Custom Order
function sort_sites_by_order($a, $b){

    // ascending (aufsteigend)
    return $a[\'blog_order\'] - $b[\'blog_order\'];

    // descending (absteigend, der juengste Artikel zuerst)
    // return $b[\'blog_order\'] - $a[\'blog_order\'];
}
usort($all_standorte, \'sort_sites_by_order\');