This removes the `g_PlayerbaseTypes` global from rmgen2, as this prevents adoption from `playerPlacementByPattern()` by rmgen1 maps (since they would need to depend on rmgen2 for that).
Since the information if walls can safely be placed is still necessary, these vales are moved inside `playerPlacementByPattern()`.
This is an easier solution than D5082 (which solves the same problem, but more complicated and possibly also more unfair).