Fast retrieval support

[ingar]

Summary

Send the fast retrieval flag along with the proposal and track it in the ClientDeal and MinerDeal. Also return this flag in the deal status query.

Resolves #285

[codecov-commenter]

Codecov Report

Merging #305 into master will decrease coverage by 0.02%.
The diff coverage is 44.45%.

@@            Coverage Diff             @@
##           master     #305      +/-   ##
==========================================
- Coverage   63.32%   63.31%   -0.01%     
==========================================
  Files          41       41              
  Lines        2538     2545       +7     
==========================================
+ Hits         1607     1611       +4     
- Misses        810      813       +3     
  Partials      121      121              

Impacted Files	Coverage Δ
storagemarket/impl/client.go	3.26% <0.00%> (-0.01%)	⬇️
storagemarket/impl/provider.go	4.43% <0.00%> (-0.03%)	⬇️
storagemarket/types.go	0.00% <ø> (ø)
storagemarket/impl/clientstates/client_states.go	89.92% <100.00%> (+0.27%)	⬆️
...oragemarket/impl/providerstates/provider_states.go	86.12% <100.00%> (+0.08%)	⬆️
storagemarket/network/libp2p_impl.go	77.97% <100.00%> (ø)

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[hannahhoward]

Missing a component of the ticket:

Augment StorageProviderNode's OnDealComplete to take fast retrieval boolean

Ideally integration test should verify this bool matches when OnDealComplete is called on the testnode

[hannahhoward]

Otherwise LGTM

[ingar]

Note about changing the StorageProviderNode interface. That method gets passed a MinerDeal, which now has a FastRetrieval bool in it. I'm passing the FastRetrieval flag in via this existing parameter; it will avoid interface churn, unless we need the interface change for some other reason.