Narrow down the contents we queue toCheck on startup

[neelvirdy]

We shouldn't queue every pinned content to be rechecked on startup. We should only need to queue contents that we may need to make more deals for.

Could we track active_deal_count per content and filter for active_deal_count < REPLICA_TARGET?

Maybe we just batch this process so we dont oversaturate the queue on startup when we're behind?

https://github.com/application-research/estuary/blob/33cc5415491f5dafa92239d2bd1524fa789aedb4/contentmgr/queue.go#L136