Update comps algorithm to save instruno in addition to parid

[jeancochrane]

It's currently difficult to work with the output of our comps algorithm because it saves the PIN of each comp sale (parid) but not the doc number (instruno), so we have to infer which sale is the comp if the PIN has multiple sales in the training set. It would be easier to use the comps data if we also saved the doc number so that each comp could be uniquely tied to a specific sale.

[jeancochrane]

Superseded by https://github.com/ccao-data/pinval/issues/7.