[ticket/11459] Do not take files of extensions into account

PHPBB3-11459
[ticket/11459] Create schema.json from migration files

PHPBB3-11459
[ticket/11459] Do not add table schema to database schema files

PHPBB3-11459
[ticket/11459] Regenerate schema files

PHPBB3-11459
[ticket/11459] Clean up a little more

PHPBB3-11459
[ticket/11459] Install DB schema from json file

PHPBB3-11459
[ticket/11459] Correctly set up the database from schema in unit tests

PHPBB3-11459
[ticket/11459] Fix auth provider test

user_timezone has no default value anymore

PHPBB3-11459