Start calculating and reporting contest scores

[adamavenir]

We can surface contest scores (total amt of slices earned)

For example, the contest scores earned by the top 4 finishers in contest 81 are:

warden	score
leastwood	25.99348907
ShippooorDAO	10.0597871125
cmichel	10.02714907
TomFrenchBlockchain	7.97548407

These aggregate contest scores can then be used in other stats in interesting ways like comparing:

• all contest scores across all time (eg what's the highest all time contest score?)
• a warden's average contest score and average contest score percentile

[joshuashort]

This issue is getting expanded to include changes required for adding a score column to findings.csv