MinimapFuncBox.cs: added Spring-AI list to "AddAI" button

Other files: Added SpringStore.cs, which cache Spring-AI list because getting them from Unitsync everytime is expensive (UnitSync.cs interface might be guilty for this high cost, but that's for later).

SpringsettingForm.cs: also use cached Springsetting list (only saved 270ms, but added benefit that it will never run Spring.exe to get the list)