Games can be started directly from the command line using the -autostart option. Some gamesettings are settable from the command line too. These are implemented manually. Especially the maps and victory conditions manually load their respective json's. Since this logic is already present on the js side in the gamesettings, this leads to duplication. When renaming things on the js side (rP26393), I ran into this forgetting about the Gamesetup.cpp, see #6433.
Instead we should reuse the js logic from the cpp. I reuse the autostart gui page, currently used for loading the tutorial.
While at it: don't uselessly create gameAttributes when we are just a client (the host decides what the settings!)
This patch fixes #6433.