[ticket/11998] Add symfony/console as dependency.

PHPBB3-11998
[ticket/11998] Basic console application script.

PHPBB3-11998
[ticket/11998] Use container to get all commands using 'console.command' tag.

PHPBB3-11998
[ticket/11998] Also setup extension class loader.

PHPBB3-11998
[ticket/11998] Add console command for recalculating email hash.

PHPBB3-11998
[ticket/11998] Move application file to bin/phpbbcli.php

PHPBB3-11998
[ticket/11998] Add phpBB abstraction for application and command.

PHPBB3-11998
[ticket/11998] Turn develop/extensions.php into console commands.

PHPBB3-11998
Merge pull request #1849 from bantu/ticket/11998

[ticket/11998] Introduction of the phpBB Console