Pull data needed for new /stats page metrics from NFTPort api

[JeffLowe]

To power the new stats page market metrics (built out in #1597), we will be pulling data from the NFTPort api.
Be sure to use similar fetch/refresh strategy that we currently use for the other two metrics.

https://www.nftport.xyz/ https://docs.nftport.xyz/docs/nftport/b3A6NDE5OTE3MjU-retrieve-reports-on-nf-ts-data