Core/Maps: Changed functions checking if map can be entered to use TransferAbortReason directly instead of intermediate Map::EnterState enum

Port From (https://github.com/TrinityCore/TrinityCore/commit/c3e1ff90a5a217691990ea4662bcaa2405b57fde)

Source/Framework/Constants/MapConst.cs

@@ -178,24 +178,6 @@ namespace Framework.Constants
         Max
     }
 
-    public enum EnterState
-    {
-        CanEnter = 0,
-        CannotEnterAlreadyInMap = 1, // Player Is Already In The Map
-        CannotEnterNoEntry, // No Map Entry Was Found For The Target Map Id
-        CannotEnterUninstancedDungeon, // No Instance Template Was Found For Dungeon Map
-        CannotEnterDifficultyUnavailable, // Requested Instance Difficulty Is Not Available For Target Map
-        CannotEnterNotInRaid, // Target Instance Is A Raid Instance And The Player Is Not In A Raid Group
-        CannotEnterCorpseInDifferentInstance, // Player Is Dead And Their Corpse Is Not In Target Instance
-        CannotEnterInstanceBindMismatch, // Player'S Permanent Instance Save Is Not Compatible With Their Group'S Current Instance Bind
-        CannotEnterAlreadyCompletedEncounter, // Player is locked to encounter that wasn't defeated in the instance yet
-        CannotEnterTooManyInstances, // Player Has Entered Too Many Instances Recently
-        CannotEnterMaxPlayers, // Target Map Already Has The Maximum Number Of Players Allowed
-        CannotEnterZoneInCombat, // A Boss Encounter Is Currently In Progress On The Target Map
-        CannotEnterInstanceShuttingDown,
-        CannotEnterUnspecifiedReason
-    }
-
     public enum ModelIgnoreFlags
     {
         Nothing = 0x00,

Source/Framework/Constants/PlayerConst.cs

@@ -240,6 +240,7 @@ namespace Framework.Constants
         DifficultyNotFound = 22,  // Client Writes To Console "Unable To Resolve Requested Difficultyid %U To Actual Difficulty For Map %D"
         XrealmZoneDown = 24,  // Transfer ed: Cross-Realm Zone Is Down
         SoloPlayerSwitchDifficulty = 26,  // This Instance Is Already In Progress. You May Only Switch Difficulties From Inside The Instance.
+        NotCrossFactionCompatible = 33,  // This instance isn't available for cross-faction groups
     }
 
     public enum RaidGroupReason