[ticket/11716] Convert Soft Delete Mod to post/topic visibility

PHPBB3-11716
[ticket/11716] Rename migration files and add note that it's converting a MOD

PHPBB3-11716
Merge remote-tracking branch 'EXreaction/ticket/11716' into develop

* EXreaction/ticket/11716:
  [ticket/11716] Rename migration files and add note that it's converting a MOD
  [ticket/11716] Convert Soft Delete Mod to post/topic visibility
Merge branch 'develop' of https://github.com/phpbb/phpbb into develop

# By Dhruv (14) and erangamapa (14)
# Via Dhruv (6) and Joas Schilling (6)
* 'develop' of https://github.com/phpbb/phpbb: (28 commits)
  [ticket/11288] Add unit test cases for foo-bar like queries
  [ticket/11288] Handle +,- without preceeding whitespace characters
  [ticket/11271] Make path conversion more precise
  [ticket/11271] limit absolute path conversion to attachment links only
  [ticket/11271] Add docblock of feed_generate_content( )
  [ticket/11271] Fix tabs and use !empty( ) instead of count( )
  [ticket/11271] Remove unnecessary inclusion of functions_display
  [ticket/11271] Typecast forum and topic id to integer
  [ticket/11271] Use absolute path for displaying inline attachments in feeds
  [ticket/11271] Changed executable bit.
  [ticket/11271] Formatting code and removing null assignment.
  [ticket/11271] Removing unnecessary database object
  [ticket/11271] Separated attachment fetching query
  [ticket/11271] Fetched feed attachments before loop.
  [ticket/11271] Removed in-line attachment comments properly.
  [ticket/11271] Displaying in-line attached images in ATOM feed.
  [ticket/11271] Add the inline images html to content
  [ticket/11271] Use class variable $db instead of global
  [ticket/11288] Handle +,- without preceeding whitespace characters
  [ticket/11271] Typecast forum and topic id to integer
  ...
[ticket/12260] Add core events to delete_posts() function.

Events for extensions to perform additional actions on posts deletion.

PHPBB3-12260
Merge remote-tracking branch 'rxu3/ticket/12260' into develop

* rxu3/ticket/12260:
  [ticket/12260] Add core events to delete_posts() function.