Implement function get_building_ids_in_boundary()

Implement the function get_building_ids_in_boundary(), a derivative function of _get_features_in_boundary(). Just like the function get_ghsl_ids_in_boundary(), this function's aim is to make it so the user does not need to use more arguments as inputs than necessary. The functions main purpose is for its use within the EntityInitializer's insert_buildings() and multiprocess_insert_buildings() functions.