[ticket/12241] Event to add and/or modify acp_board configurations

PHPBB3-12241
[ticket/12241] Move $phpbb_dispatcher to the top

PHPBB3-12241
[ticket/12241] Add submit to event variables

PHPBB3-12241
[ticket/12241] Update event name and version match our guidelines

PHPBB3-12241
[ticket/12241] Add @var for the arguments

PHPBB3-12241
Merge pull request #2126 from nickvergessen/ticket/forumhulp/12241

[ticket/12241] Event to add and/or modify acp_board configurations