lower timeouts for deals/retrievals

[SgtPooki]

#263 lowers timeouts to 10m for deals and 5m for retrievals. I will update that PR to lower to 6m (deals) and 1m (retrievals)

This issue is tracking lowering them even further: 3m for deals, 30s for retrievals. with the current avg throughput showing on staging dealbot:

uploads at 175.7 KB/s take 60s
downloads at 2.9 MB/s take 3.6s

the limits of 3m for deals would mean if upload takes 60s, we have 120s for: chain verification & downloading from the SP to verify it.

related to #263

[SgtPooki]

it seems like some deals are still running past the 6m time limit set in #263. I think we need to get filecoin-project/filecoin-pin#332 in and pipe signals through there to ensure synapse-sdk operations are aware of our time constraints.