[ticket/12372] Use jQuery in javascript dE() function

PHPBB3-12372
[ticket/12372] Unify definition of function dE() across all files

PHPBB3-12372
[ticket/12372] Move dE() function core.js

PHPBB3-12372
[ticket/12372] Rename JS function dE() to phpbb.toggleDisplay()

PHPBB3-12372
[ticket/12372] Use admin.js $(document).ready for hiding questionnaire details

PHPBB3-12372
[ticket/12372] Use $() instead of jQuery() in core.js for toggleDisplay

PHPBB3-12372
[ticket/12004] Support empty routes to app.php/ in path_helper

The symfony routing component allows us to use the path "/" for routes.
Therefore, we should be able to use example.com/app.php/ for controllers.
However, this currently does not properly work. The method get_web_root_path
incorrectly returns phpbb_root_path. Therefore, paths to images or files are
broken.

PHPBB3-12004
Merge remote-tracking branch 'marc/ticket/12372' into develop-ascraeus

* marc/ticket/12372:
  [ticket/12372] Use $() instead of jQuery() in core.js for toggleDisplay
  [ticket/12372] Use admin.js $(document).ready for hiding questionnaire details
  [ticket/12372] Rename JS function dE() to phpbb.toggleDisplay()
  [ticket/12372] Move dE() function core.js
  [ticket/12372] Unify definition of function dE() across all files
  [ticket/12372] Use jQuery in javascript dE() function
Merge remote-tracking branch 'marc/ticket/12004' into develop-ascraeus

* marc/ticket/12004:
  [ticket/12004] Support empty routes to app.php/ in path_helper