[Quest API] Add commify to Perl/Lua. (#2099)

- Add quest::commify(number) to Perl.
- Add eq.commify(number) to Lua.

common/string_util.cpp

@@ -1265,3 +1265,24 @@ std::string ConvertMoneyToString(uint32 platinum, uint32 gold, uint32 silver, ui
 	}
 	return money_string;
 }
+
+std::string commify(const std::string &number) {
+	std::string temp_string;
+
+	auto string_length = static_cast<int>(number.length());
+
+	int i = 0;
+	for (i = string_length - 3; i >= 0; i -= 3) {
+		if (i > 0) {
+			temp_string = "," + number.substr(static_cast<unsigned long>(i), 3) + temp_string;
+		} else {
+			temp_string = number.substr(static_cast<unsigned long>(i), 3) + temp_string;
+		}
+	}
+
+	if (i < 0) {
+		temp_string = number.substr(0, static_cast<unsigned long>(3 + i)) + temp_string;
+	}
+
+	return temp_string;
+}