Only store fresh signed data

[Siegrift]

Currently, we do not store active dAPIs in state which means that we need to store the signed data for every beacon even if there are only a few active beacons among the active dAPIs.

Another side effect of this is that once we fetch a data for a beacon, we persist it forever.

[aquarat]

We store dapiNames received from the contract in the state, so the signed data fetch loop can just filter incoming samples by active dAPIs. I'll do this.

[Siegrift]

I remember we discussed the first part (only saving data for active dAPIs) in the spec and @bbenligiray wasn't sold on this.

Another side effect of this is that once we fetch a data for a beacon, we persist it forever.

We didn't discuss this which feels to me is a reason of itself to implement this. We should discuss this at the weekly call.

I'll do this.

Yeah, go ahead.

[aquarat]

It was decided in the call to (1) not store active dapis in the state and (2) purge the signed data store by timestamp (> 24 hours) and not by active dapis.

[Siegrift]

Can you change the issue title as well?