[7394] Check loot_template.maxcount for max allowed value (255) and make better report for this case.

Also optimize strcture LootStoreItem that let use 4 byte for loot template element in memory instead 5 bytes.
But limit group id to 127 max value. Check this at loading.

src/game/AchievementMgr.cpp

@@ -606,7 +606,6 @@ void AchievementMgr::UpdateAchievementCriteria(AchievementCriteriaTypes type, ui
                 {
                     if(Player::GetDrunkenstateByValue(GetPlayer()->GetDrunkValue()) != DRUNKEN_SMASHED)
                         continue;
-                    // TODO: hardcoding eventid is bad, it can differ from DB to DB - maye implement something using HolidayNames.dbc?
                     if(!IsHolidayActive(HOLIDAY_BREWFEST))
                         continue;
                 }