Autoretrieve Stats - Data Ingestion

[jcace]

Modify Autoretrieve to collect an event stream of all retrievals, and write it to our retrieval event database.

This should be possible by implementing a Lassie RetrievalSubscriber in Autoretrieve, and then wiring it up so that every time a retrieval event fires we will save the data to the database.

This will depend on getting our database/schema figured out ref: #873

[jcace]

Updated task description:

1. Add an endpoint to estuary-metrics to be POST'ed to with retrieval stats. It will follow the struct defined here:
   https://github.dev/filecoin-project/lassie/blob/main/pkg/eventrecorder/eventrecorder.go#L63

2. Configure autoretrieve to use Lassie Event Publisher to publish events to estuary metrics API (it is configured by this line here)
   https://github.dev/application-research/autoretrieve/blob/master/autoretrieve.go#L197

[jcace]

estuary-metrics task: application-research/estuary-metrics#18