Core/Items: Implement azerite essences

Port From (https://github.com/TrinityCore/TrinityCore/commit/ec9d624aec9e0a39b1bcee7d4077f46be358faad)

Source/Game/DataStorage/Structs/A_Records.cs

@@ -254,12 +254,42 @@ namespace Game.DataStorage
         public byte ConsignmentRate;
     }
 
+    public sealed class AzeriteEssenceRecord
+    {
+        public string Name;
+        public string Description;
+        public uint ID;
+        public int SpecSetID;
+    }
+
+    public sealed class AzeriteEssencePowerRecord
+    {
+        public uint ID;
+        public string SourceAlliance;
+        public string SourceHorde;
+        public int AzeriteEssenceID;
+        public byte Tier;
+        public uint MajorPowerDescription;
+        public uint MinorPowerDescription;
+        public uint MajorPowerActual;
+        public uint MinorPowerActual;
+    }
+
     public sealed class AzeriteItemRecord
     {
         public uint ID;
         public uint ItemID;
     }
 
+    public sealed class AzeriteItemMilestonePowerRecord
+    {
+        public uint ID;
+        public int RequiredLevel;
+        public int AzeritePowerID;
+        public int Type;
+        public int AutoUnlock;
+    }
+
     public sealed class AzeriteKnowledgeMultiplierRecord
     {
         public uint ID;
@@ -273,4 +303,13 @@ namespace Game.DataStorage
         public ulong MinimumExperienceToNextLevel;
         public uint ItemLevel;
     }
+
+    public sealed class AzeritePowerRecord
+    {
+        public uint ID;
+        public uint SpellID;
+        public int ItemBonusListID;
+        public int SpecSetID;
+        public int Flags;
+    }
 }

Source/Game/DataStorage/Structs/S_Records.cs

@@ -166,6 +166,13 @@ namespace Game.DataStorage
         public byte DisplayOrder;
     }
 
+    public sealed class SpecSetMemberRecord
+    {
+        public uint ID;
+        public uint ChrSpecializationID;
+        public uint SpecSetID;
+    }
+
     public sealed class SpellAuraOptionsRecord
     {
         public uint Id;