[ticket/13123] Add events to allow modifying post data

PHPBB3-13123
[ticket/11224] Revert "Merge pull request #2460 from Nicofuma/ticket/11224"

This reverts commit d26436944173d1fa28a1abd96bca861381246860, reversing
changes made to 75fcfb1c1d68f1632e7beae3f59699ddff8e5292.

PHPBB3-11224
[ticket/13119] Add another event which is triggered independent from actions

PHPBB3-13119
Merge pull request #3015 from nickvergessen/ticket/13119

[ticket/13119] Add another event which is triggered independent from actions
Merge pull request #3012 from nickvergessen/ticket/13123

[ticket/13123] Add events to allow modifying post data

* nickvergessen/ticket/13123:
  [ticket/13123] Add events to allow modifying post data
Merge pull request #6 from phpbb/develop-ascraeus

follow up changes