[feature/auth-refactor] Have a base auth class

PHPBB3-9734
[feature/auth-refactor] Prevent fatal error in php < 5.3.23

PHPBB3-9734
[feature/auth-refactor] Remove implements on classes extending base

PHPBB3-9734
[feature/auth-refactor] Change 'must' to 'should'

PHPBB3-9734
[feature/auth-refactor] Code style fix for doc blocks

PHPBB3-9734
[feature/auth-refactor] Remove full stop

PHPBB3-9734
[feature/auth-refactor] Check that providers implement auth interface

PHPBB3-9734
[feature/auth-refactor] Remove invalid providers from acp select

PHPBB3-9734
[ticket/11626] Create get_acp_template method for auth providers

PHPBB3-11626
[ticket/11626] LDAP Auth ACP Template File

PHPBB3-11626
[ticket/11626] Include the template file in acp_board

PHPBB3-11626
[ticket/11626] Change interface to match functionality

Changes the interface so that it matches the new functionality of
phpbb_provider_auth_interface::acp().

PHPBB3-11626
[ticket/11626] Call method only one time per provider

PHPBB3-11626
[ticket/11626] Change the identifier template file in the template

PHPBB3-11626
[ticket/11626] Make identifier uppercase per style requirements

PHPBB3-11626
[feature/auth-refactor] Fix typo

PHPBB3-9734
[feature/auth-refactor] Fix style issue

PHPBB3-9734
[feature/auth-refactor] Test that acp_board excludes invalid providers

PHPBB3-9734
[feature/auth-refactor] Move test classes into separate directory

PHPBB3-9734
[feature/auth-refactor] Code style change

PHPBB3-9734