Refactor `lift_order`-logic from `MultiOrderModel` to `algorithms`

[M-Lampert]

The methods

• lift_order_edge_index
• lift_order_edge_index_weighted
• aggregate_edge_index potentially have uses outside of MultiOrderModel, e.g. for the centrality calculations. Since they are static methods anyway, it would make sense to separate them from the class altogether and put the into utils or algorithms`.