[ticket/11458] Search for permission language files in extensions

Extensions that add new permission masks only need to add a permission file in
the language folder of the extension. The file must start with 'permissions_'
eg 'permissions_blog.php'. The permission language file will be automatically
included when viewing/setting permissions.

PHPBB3-11458
[ticket/11482] Implementation of advanced DEFINE tag

Implementation of advanced DEFINE tag and ENDDEFINE

PHPBB3-11482
[ticket/11482] Unit tests for advanced DEFINE

Unit tests for advanced DEFINE and ENDDEFINE

PHPBB3-11482
[ticket/11482] Use double quotes for code

Use double quotes for code to avoid excessive escaping

PHPBB3-11482
[ticket/11458] We still auto add language files from the mods and acp
folders in the language directory, so we revert some changes here

PHPBB3-11458
[ticket/11458] Add functional test

Since there is no test method to include extension language files, a
functional test seems more appropriate.
We add a permission mask 'acl_u_foo' with translation found in extenion
'bar' and confirm that the permission language file 'permissions_foo.php'
from 'bar' was added by asserting that 'Can view foo' exists when viewing
user permissions in acp

PHPBB3-11458
[ticket/11458] Fix test

PHPBB-11458
[ticket/11458] Fix functional test again

Add 'u_foo' to phpbb_acl_options
Make sure extension and fixtures are added before running test

PHPBB3-11458
[ticket/11413] Schema changes and migration file

Notifications tables are dropped because phpBB currently does not have
any way to make the necessary changes to the DB schema (and no release
has yet been made with these changes).

This will fix the following bugs:
PHPBB3-11411
PHPBB3-11413
PHPBB3-11414
PHPBB3-11416
PHPBB3-11420

PHPBB3-11413
[ticket/11413] Rename columns in notification/manager.php

PHPBB3-11413
[ticket/11413] Undo editing the user_notifications table

item_type is not equivalent to notification_type_name, it can be a generic
string (typically used to be able to subscribe to multiple notification
types while only subscribing to one item

PHPBB3-11413
[ticket/11413] Prevent recursive function calls

PHPBB3-11413
[ticket/11413] Fix notification tests

Send types/methods the cache service, not the driver (not sure why the
driver was sent before)

PHPBB3-11413
[ticket/11413] Fix some more tests

PHPBB3-11413
[ticket/11413] Fix test fixtures and tests

PHPBB3-11413
[ticket/11413] Create test for notification conversion

PHPBB3-11413
[ticket/11413] Use sql_insert_buffer

PHPBB3-11413
[ticket/11413] Test get_notification_type_id and _ids functions

PHPBB3-11413
[ticket/11413] Don't use the database for the convert test

Different databases seem to work slightly differently here and are causing
errors

PHPBB3-11413
[ticket/11413] Include mock class

PHPBB3-11413