[ticket/10073] Deduplicate posting buttons code in ACP

PHPBB3-10073
[ticket/10073] Change name of the ACP module

PHPBB3-10073
[ticket/10073] Make contact page available when board is disabled

PHPBB3-10073
[ticket/10073] Move template code into the template

PHPBB3-10073
[ticket/10073] Fix more "Contact Us" strings

PHPBB3-10073
[ticket/10073] Get service from container

PHPBB3-10073