Make CustomizeBuildings config easier to read for other mods, example included

[Sgt-Imalas]

Adds a static method to the mod config of CustomizeBuildings.

this helps other mods to more easily read config values of the mod for better intra-mod compatibility.

the class Customize_Buildings_ModIntegration is an example of such an integration, it can be directly copied by other mods.

Those mods then can call Customize_Buildings_ModIntegration.TryGetConfigValue to read config state values without any further requirements