Add information about fees in PairDayData

[albydeca]

Hi, it would be great to see data regarding 24h fees inside the daily data on pairs, as is available on the official Sushi stats page: https://analytics.sushi.com/

Uni v3 subgraph also usefully provides this: https://thegraph.com/hosted-service/subgraph/uniswap/uniswap-v3

Thanks :)

[matthewlilley]

@albydeca this repo is somewhat depreciated, these are available here:

https://github.com/sushiswap/subgraphs/blob/master/subgraphs/legacy-exchange/schema.graphql#L107