Change the way CK3 development from I:R is calculated (#1971) #patch

Previously, the development calculated for a CK3 province was an average
of the civilisation values from corresponding Imperator provinces. Now
it's a sum.

ImperatorToCK3/CK3/Titles/LandedTitles.cs

@@ -1143,7 +1143,7 @@ double CalculateCountyDevelopment(Title county, IReadOnlyDictionary<ulong, int>
 						continue;
 					}
 
-					dev += sourceProvinces.Average(srcProv => srcProv.CivilizationValue / ck3ProvsPerIRProv[srcProv.Id]);
+					dev += sourceProvinces.Sum(srcProv => srcProv.CivilizationValue / ck3ProvsPerIRProv[srcProv.Id]);
 				}
 
 				dev *= irCivilizationWorth;