Arbitrary starting resources in the gamesetup

[elexis]

The current starting resources setting in the gamesetup is a multiple choice decision. Depending on which value is selected (low, medium, high, very high, deathmatch...), the same amount is given for each resource.

It were great if the players could specify custom starting resources, for example 500 food, 2000 wood, 300 metal, 300 stone, to be able to shape the playability, pace and required strategy of the game wisely in advance.

There should be one setting (either dropdown or text input) per resource. It should likely use the format Food: 500 <food_icon>.

So as not to rewrite the feature, #4381 should be done before probably.