WesnothMap: add code used by the [map] tag support.

It must be configured in the ACP with the following parameters:

bbCode spec.: [map]{TEXT}[/map]

HTML: <form name="Wesnoth Map Button" target="_blank"
            action="includes/WesnothMap.php" method="post">
            <input type="hidden" name="wesnoth_map_data" value="{TEXT}">
            <input type="submit" value="Display Map">
      </form>
(cherry picked from commit ec8681afcedd711b0491090d00a0ad7717a417ce)
Wesnoth mod: apply shadowmaster's wesnothd usernames compatibility check
(cherry picked from commit bd0de2c387e8b4e23d76d17b3ed9f5805d493fec)
Wesnoth mod: apply the Beyond Limits and Jetrel attachment quota overrides, and Jetrel's PM limit override
(cherry picked from commit 45e1a3d3536c60eee47e605a6bd1827a253adf6d)
Session Manager: point to #wesnoth @ irc.freenode.net when board is disabled via ACP

This only works when board_disable_msg is set to a non-empty string and
doesn't play well with language macros.
Introduce soft requirement of being >= 13 for registering
Wesnoth mod: Fix the Jetrel detection code so it doesn't make PostgreSQL croak
Wesnoth mod: Hide viewtopic profile information for users with primary group id 6649 (Forum Services)
Wesnoth mod: Hide users with primary group id 6649 (Forum Services) from the general memberlist

They are still displayed if someone uses a specific memberlist mode.
Main: disable the Team memberlist view
Support Toolkit/contrib/acp_link.xml: apply mod version ???

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