feat(Core/Misc): change how Position struct is retrieved (#9017)

Update Position::GetPosition() and similar methods signatures to reflect 2a4c9bc changes by return a Position object instead of accepting a Position parameter by reference.

Cherry pick of https://github.com/TrinityCore/TrinityCore/commit/2585e799f95f259dd4b422daf15ef7963173c408

src/server/scripts/EasternKingdoms/BlackrockMountain/BlackrockSpire/boss_the_beast.cpp

@@ -62,8 +62,7 @@ public:
     bool Execute(uint64 /*time*/, uint32 /*diff*/) override
     {
         _me->SetReactState(REACT_PASSIVE);
-        Position movePos;
-        _me->GetRandomPoint(OrcsRunawayPosition, 10.0f, movePos);
+        Position movePos = _me->GetRandomPoint(OrcsRunawayPosition, 10.0f);
         _me->GetMotionMaster()->MovePoint(1, movePos);
         return true;
     }