Missing offline logo in the diplomacy window in game

[fpre_O_O_O_O_O_O]

There should be an offline icon in the diplomacy window, in the column where the defeated state is shown or better in an extra column.

So you can always see the connection state of the players.

[elexis]

The diplomacy dialog should be reserved for ingame states, ideally only diplomacy.

Instead we should add a separate list for all networked clients #3787 so that you have a nice list of observers, network stats, kick/ban buttons, the late-observer setting and anything else in one place too.