Add: Industry accepted and waiting history graphs.

Records amount of cargo accepted, and a rolling average of the waiting amount.

Average waiting samples the waiting amount once per day for each industry, spread out over an economy day.

src/industry_cmd.cpp

@@ -1245,6 +1245,10 @@ void OnTick_Industry()
 
 	for (Industry *i : Industry::Iterate()) {
 		ProduceIndustryGoods(i);
+
+		if ((TimerGameTick::counter + i->index) % Ticks::DAY_TICKS == 0) {
+			for (auto &a : i->accepted) a.accumulated_waiting += a.waiting;
+		}
 	}
 }
 
@@ -2505,6 +2509,14 @@ static void UpdateIndustryStatistics(Industry *i)
 			RotateHistory(p.history);
 		}
 	}
+
+	for (auto &a : i->accepted) {
+		if (!IsValidCargoType(a.cargo)) continue;
+		if (a.history == nullptr) continue;
+
+		(*a.history)[THIS_MONTH].waiting = GetAndResetAccumulatedAverage<uint16_t>(a.accumulated_waiting);
+		RotateHistory(*a.history);
+	}
 }
 
 /**