Core/Items: Updated heart of azeroth level cap and knowledge starting date for 8.3

Port From (https://github.com/TrinityCore/TrinityCore/commit/ac671cc7ecfbc0a2ac56337dba753a22737d92a2)

Source/Framework/Constants/PlayerConst.cs

@@ -67,7 +67,7 @@ namespace Framework.Constants
 
         //Azerite
         public const uint ItemIdHeartOfAzeroth = 158075;
-        public const uint MaxAzeriteItemLevel = 70;
+        public const uint MaxAzeriteItemLevel = 129;
         public const uint MaxAzeriteItemKnowledgeLevel = 30;
         public const uint PlayerConditionIdUnlockedAzeriteEssences = 69048;
         public const uint SpellIdHeartEssenceActionBarOverride = 298554;

Source/Game/Entities/Item/AzeriteItem.cs

@@ -228,9 +228,9 @@ namespace Game.Entities
 
         uint GetCurrentKnowledgeLevel()
         {
-            // count weeks from 26.06.2019
+            // count weeks from 14.01.2020
             DateTime now = GameTime.GetDateAndTime();
-            DateTime beginDate = new DateTime(2019, 6, 26);
+            DateTime beginDate = new DateTime(2020, 1, 14);
             uint knowledge = 0;
             while (beginDate < now && knowledge < PlayerConst.MaxAzeriteItemKnowledgeLevel)
             {