[ticket/11138] Increase AJAX timeout period to 15 seconds.

PHPBB3-11138
[ticket/11138] Do not use AJAX for ACP resync features.

PHPBB3-11138
Merge remote-tracking branch 'prototech/ticket/11138' into develop

* prototech/ticket/11138:
  [ticket/11138] Do not use AJAX for ACP resync features.
  [ticket/11138] Increase AJAX timeout period to 15 seconds.
  [ticket/11872] Template syntax typos in oauth templates