Rewrite/restructure gamesetup

[leper]

Currently gamesetup.js is not really extensible to support trigger/campaign maps where some settings should be fixed while others can be changed (e.g. allowing the player to assign himself to slots 1 and 3 on a 4 player map). The logic to decide what settings can be changed (for RMS, Skirmish Maps, and Scenarios) is also quite duplicated.

The code could also use some improvement such that the persistent game settings can work with just storing the minimum of information needed to recreate the settings instead of saving everything and then hoping that it doesn't cause conflicts/issues later (see #3044, #3033).

See also #3013.

[Itms]

In 16346:

Some hacks to fix game setup persisting problems, patch by @aBothe.
Fixes #3033, #3034.

The whole gamesetup.js system should be eventually re-factored to remove those hacks and to improve the robustness of the code: see #3049.

[Alex]

Is there a gamesetup-wishlist?

Things like the ability that each player in a networked gamesetup should be able to choose his/her own civ/color/position - perhaps a more AOE-like behaviour could be taken, so that colors are hardwired to positions or such.

Anyway, yes, gamesetup needs a rewrite.

[Stan]

If you could have a look at #1580 I'd be happy :) else #1834 also #812

:)

[fabio]

See also #3013.