Core/Transports: ported transport refactoring

* this implements full support for stoppable transports as well as serverside transport position tracking
* fixed several vehicle related issues
* fixed gameobject passengers not being displayed as transport passengers
* pets, dynamic objects and other summons are not added as transport passengers and will now properly be displayed
Todo:
- Deeprun Tram visual issues needs to be resolved
- Lady Deathwhisper's elevator needs some additional research

src/server/scripts/Commands/cs_npc.cpp

@@ -347,7 +347,7 @@ public:
         Player* chr = handler->GetSession()->GetPlayer();
         Map* map = chr->GetMap();
 
-        if (Transport* trans = chr->GetTransport())
+        if (MapTransport* trans = chr->GetMapTransport())
         {
             ObjectGuid::LowType guid = map->GenerateLowGuid<HighGuid::Unit>();
             CreatureData& data = sObjectMgr->NewOrExistCreatureData(guid);