Core/Maps: add new FLAG_ALLIANCE_ONLY and FLAG_HORDE_ONLY for instance spawn groups

Port From (https://github.com/TrinityCore/TrinityCore/commit/203dfec2a1d1d628469ed0d68fefac33c15e65d6)

Source/Framework/Constants/MapConst.cs

@@ -239,8 +239,10 @@ namespace Framework.Constants
     {
         ActivateSpawn = 0x01,
         BlockSpawn = 0x02,
+        AllianceOnly = 0x04,
+        HordeOnly = 0x08,
 
-        All = (ActivateSpawn | BlockSpawn)
+        All = ActivateSpawn | BlockSpawn | AllianceOnly | HordeOnly
     }
 
     public enum AreaHeaderFlags : ushort

Source/Game/Globals/ObjectManager.cs

@@ -5677,6 +5677,12 @@ namespace Game
                 else
                     info.Flags = flags;
 
+                if (flags.HasFlag(InstanceSpawnGroupFlags.AllianceOnly) && flags.HasFlag(InstanceSpawnGroupFlags.HordeOnly))
+                {
+                    info.Flags = flags & ~(InstanceSpawnGroupFlags.AllianceOnly | InstanceSpawnGroupFlags.HordeOnly);
+                    Log.outError(LogFilter.Sql, $"Instance spawn group ({instanceMapId},{spawnGroupId}) FLAG_ALLIANCE_ONLY and FLAG_HORDE_ONLY may not be used together in a single entry - truncated to {info.Flags}.");
+                }
+
                 _instanceSpawnGroupStorage.Add(instanceMapId, info);
 
                 ++count;

Source/Game/Maps/Instances/InstanceScript.cs

@@ -217,6 +217,7 @@ namespace Game.Maps
         }
 
         enum states { Block, Spawn, ForceBlock };
+
         void UpdateSpawnGroups()
         {
             if (_instanceSpawnGroups.Empty())
@@ -234,8 +235,13 @@ namespace Game.Maps
                 if (((1 << (int)GetBossState(info.BossStateId)) & info.BossStates) == 0)
                     continue;
 
+                if (((instance.GetTeamIdInInstance() == TeamId.Alliance) && info.Flags.HasFlag(InstanceSpawnGroupFlags.HordeOnly))
+                    || ((instance.GetTeamIdInInstance() == TeamId.Horde) && info.Flags.HasFlag(InstanceSpawnGroupFlags.AllianceOnly)))
+                    continue;
+
                 if (info.Flags.HasAnyFlag(InstanceSpawnGroupFlags.BlockSpawn))
                     newStates[info.SpawnGroupId] = states.ForceBlock;
+
                 else if (info.Flags.HasAnyFlag(InstanceSpawnGroupFlags.ActivateSpawn))
                     newStates[info.SpawnGroupId] = states.Spawn;
             }