[ticket/12348] Allow to run create_schema_files when phpBB is not installed

PHPBB3-12348
Merge remote-tracking branch 'github-nickvergessen/ticket/12348' into develop-ascraeus

* github-nickvergessen/ticket/12348:
  [ticket/12348] Allow to run create_schema_files when phpBB is not installed
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12348] Allow to run create_schema_files when phpBB is not installed