Core/BattlegroundIC:

* Fixed Catapults
* Fixed Graveyards
* Fixed Cannons on Gunships
* More Blizzlike Teleport to Gunship
* Fixed Gunship Teleport to Hangar

Closes https://github.com/TrinityCore/TrinityCore/issues/12323 and https://github.com/TrinityCore/TrinityCore/issues/9557

But it's not yet finished...

Missing waypoints (captains on transport)
Some hacks... (like in spell_ioc_gunship_portal)
This NPC is spawned only if you controll the gunship, so it's better to spawn them like this, no ?