User defined or static HOV IJ nodes

[nquisen]

Is it a quick ask to add the ability to define the starting junctions or have them start at a number that will never be used? This will help with doing scenario comparisons since one difference in projects can alter the starting node for HOVs. It will help to identify HOV after network builder is run. Also helps in keeping the network output static for exporting different scenarios to Dynameq.