[ticket/11459] Add a migration/schema_generator

It loops over the migrations and creates the schema from it.

PHPBB3-11459
[ticket/11459] Add Schema from 3.0.0

PHPBB3-11459
[ticket/11459] Use new migration/schema_generator to create schema files

PHPBB3-11459
[ticket/11459] Update schema files with new script

The order of some tables and columns was changed

PHPBB3-11459
[ticket/11459] Remove old schema file

PHPBB3-11459
[ticket/11459] Update doc blocks

PHPBB3-11459
[ticket/11459] Add migration for migrations table

This migration will always be skipped on updates, because database_update.php
creates the table. But the create schema script requires the migration,
so the table is created for new installs.

PHPBB3-11459
[ticket/11459] Correctly handle index column length

Code is copied from db\tools::sql_create_index()

PHPBB3-11459
[ticket/11459] Remove spaces from the end of lines in MSSQL

PHPBB3-11459
[ticket/11459] Refresh schema files

PHPBB3-11459
[ticket/11459] Pass array with migration class names to schema generator

PHPBB3-11459
[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] 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
[ticket/11459] Fix missing constant CONFIG_TABLE for sql_create_index()

PHPBB3-11459
[ticket/11459] Move $supported_dbms to beginning of create schema file

PHPBB3-11459