[ticket/9801] Allow display of page outside board directory on viewonline

Until now, the preg_match didn't take into account that a page might be
outside the board directory. After this change, the regular expression will
allow preceding dots and slashes. Paths like ../../test.php will be allowed.
The page will be unknown in viewonline.php and it will revert to index.php as
current page. However, the core.viewonline_overwrite_location event will
receive proper info of the page the user is on right now allowing a listener
to change the info that is being displayed.

PHPBB3-9801
[ticket/12334] Add PROFILE_FIELD_VALUEID template var

PHPBB3-12334
[ticket/12334] Added field_novalue fall-back as requested

PHPBB3-12334
[ticket/12334] Implemented get_profile_valueid method

PHPBB3-12334
[ticket/12334] Changed from valueid to value_raw

PHPBB3-12334
[ticket/12334] Added test get_profile_value_raw

PHPBB3-12334
[ticket/12334] Dropdowns cannot be tested this way

PHPBB3-12334
[ticket/12334] Removed tests

Will be implemented in #2459

PHPBB3-12334
[ticket/12334] Add get_profile_value_raw unit tests for type_int

PHPBB3-12334
[ticket/12334] Add get_profile_value_raw unit test for type_url

PHPBB3-12334
[ticket/9801] Add viewonline_helper service to allow proper testing

The viewonline_helper service can and will be extended in the future which
will allow us to also test the viewonline page better.

PHPBB3-9801
[ticket/12334] Add get_profile_value_raw unit test for type_string

PHPBB3-12334
[ticket/12334] Add get_profile_value_raw unit tests for type_dropdown

PHPBB3-12334
[ticket/12334] Add get_profile_value_raw unit test for type_date

PHPBB3-12334
[ticket/12334] Add get_profile_value_raw unit test for type_bool

PHPBB3-12334
[ticket/9801] Remove spaces before * in docblock

PHPBB3-9801
[ticket/12645] Replace support links in SUPPORT_BODY with 3.1 links

PHPBB3-12645
[ticket/12777] Rename extension status functions and add is_configured()

PHPBB3-12777
[ticket/12777] Update doc block of is_configured()

PHPBB3-12777
[ticket/12777] Add is_purged()

PHPBB3-12777