Replace the "full games" filter with an "open games" filter and exclude running games from the results (since the use-case is to help players finding a game they can join as a player).

Revert rP15978 because the reasons for hiding non-open games don't apply or don't apply anymore:

• The filter doesn't actually prevent unwanted clients to join the server.
• The host can kick or ban unwanted clients now.
• Many users are interested in joining games as observer (either for the sake of observing or to meet up with buddies). So for many players the first action after entering the lobby was to uncheck this checkbox.

Differential Revision: https://code.wildfiregames.com/D218
Reviewed By: mapkoc