undefined property g_GameAttributes.settings.Ceasefire for games with autostart

[mimo]

Start a game with (visual) autostart, and click on the ojectives button: this gives

WARNING: JavaScript warning: gui/common/gamedescription.js line 311
reference to undefined property g_GameAttributes.settings.Ceasefire
WARNING: JavaScript warning: globalscripts/l10n.js line 35
Script value conversion check failed: v.isNumber() (got type undefined)

[elexis]

The reason for that is that each logic change to gamesetup.js (mostly new options) must copy that to GameSetup.cpp. That's why I never came around to posting a complete patch, because if we fix the first property, the next one bugs. We also run into #4504 again. D592 is another issue related to that what was fixed when trying to deal with this ticket. (So not uploading 50% of a WIP now)

[bb]

In 21561:

Add a ceasire autostart option, silences a javascript warning on autostart games
fixes #4606