Surface SP trends on `filecoin_storage_providers`

[davidgasquez]

We're surfacing the latest values for a bunch of data points. We should surface also trends and averages.

Starting with Storage Provider Power, it might be interesting to derive:

• Average of Daily RBP/QAP (30, 90, 180, 265 days)
• Some growth / trend metric on RBP/QAP