state sync hangs on genesis

[lklimek]

Expected Behavior

On genesis, state sync should not block sync progress.

Current Behavior

1. Nodes wait for 2 peers that can be source of state sync, but none is available as all are on genesis and waiting.
2. We only check available snapshots when new nodes are connected, so if meanwhile the peer will get synced and get some snapshots, we will not notice it and will block indefinitely.

Possible Solution

Refactor the waiting logic.