Standardize output columns of pgr_withPoints and pgr_withPointsCost

Standardize pgr_withPoints output columns to be:

```
Returns set of (seq, path_seq, start_vid, end_vid, node, edge, cost, agg_cost)
OR EMPTY SET
```


Standardize pgr_withPointsCost to be:

```
Returns set of (start_vid, end_vid, agg_cost)
OR EMPTY SET
```