[ticket/11691] Stagger the convertion of soft delete updates

PHPBB3-11691
[ticket/11691] Stagger user notification reconversion even more

PHPBB3-11691
[ticket/11691] Change detection of effectively_installed()

When start is set for a migration, it is not yet effectively installed.
So we just continue doing it...

PHPBB3-11691
[ticket/11691] Fix some more problems with softdelete update

* wrong order of arguments on sql_query_limit
* avoid "BIGINT UNSIGNED value is out of range" errors
* increase limit for the loop

PHPBB3-11691
[ticket/11691] Fix some minor comments

PHPBB3-11691
[ticket/11691] Add order by to the query

PHPBB3-11691
[ticket/11691] Fix typo in comment

PHPBB3-11691
[ticket/11691] Move purge code into new function

PHPBB3-11691
[ticket/11691] Fix table names and arguments/docs

PHPBB3-11691
[ticket/11852] Split filesystem and path_helper into 2 classes

PHPBB3-11852
[ticket/11852] Move tests to folder with new class name

PHPBB3-11852
[ticket/11852] Add class file

PHPBB3-11852
[ticket/11862] Correct var names in user_delete() events due to prune-users

Fix comments after incorrect merge of previous PR.

PHPBB3-11862
Merge remote-tracking branch 'Marc/ticket/11862' into develop

* Marc/ticket/11862:
  [ticket/11862] Correct var names in user_delete() events due to prune-users
[ticket/11873] Do not hash very large passwords in order to safe resources.

PHPBB3-11873
[ticket/11873] Add unit test for large password input.

The password should be rejected quite fast.

PHPBB3-11873
Merge branch 'ticket/11873' into prep-release-3.0.12

* ticket/11873:
  [ticket/11873] Add unit test for large password input.
  [ticket/11873] Do not hash very large passwords in order to safe resources.
[prep-release-3.0.12] Update changelog for 3.0.12 release.
Merge branch 'prep-release-3.0.12' into develop-olympus

* prep-release-3.0.12:
  [prep-release-3.0.12] Update changelog for 3.0.12 release.
  [ticket/11873] Add unit test for large password input.
  [ticket/11873] Do not hash very large passwords in order to safe resources.
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [prep-release-3.0.12] Update changelog for 3.0.12 release.
  [ticket/11873] Add unit test for large password input.
  [ticket/11873] Do not hash very large passwords in order to safe resources.