[ticket/11363] Load module info files for extensions too

Use the acp_modules::get_module_infos function instead of our own include code

PHPBB3-11363
[ticket/11363] Fix a couple bugs and throw errors if the file not found

PHPBB3-11363
Merge remote-tracking branch 'EXreaction/ticket/11363' into develop

# By Nathaniel Guse
# Via Nathaniel Guse
* EXreaction/ticket/11363:
  [ticket/11363] Fix a couple bugs and throw errors if the file not found
  [ticket/11363] Load module info files for extensions too