related to #2165 new add user popin

- add field for add user
- in the `pwg.users.add` method, the params `send_password_by_mail` does nothing anymore. Because we no longer want to send passwords in clear text.
- in the `pwg.users.add` add a new `auto_password` parameter to generate a random password when a user is created
- use this parameter (`auto_password`) in user_list.js
- change mail content et password page on first login

ws.php

@@ -1155,6 +1155,11 @@ enabled_high, registration_date, registration_date_string, registration_date_sin
       'ws_users_add',
       array(
         'username' => array(),
+        'auto_password' => array(
+          'default'=>false,
+          'flags'=>WS_TYPE_BOOL, 
+          'info' => 'if true ignores password and confirm password'
+        ),
         'password' => array('default'=>null),
         'password_confirm' => array('flags'=>WS_PARAM_OPTIONAL),
         'email' =>    array('default'=>null),