Add toggle for different POI comparison method

[pete-eiger]

It would be good to have a toggle (this can be an environment or CLI variable) that sets the POI comparison method. Currently there is only one method (comparing the local POI with the remote POI that has the most stake tied to it), but we should add a method that compares the local POI to the most-attested one (by count of Indexers that attested it, regardless of their stake).