Epic: Lotus integration

[Kubuxu]

Acceptance criteria:

• F3 runs within lotus using its libp2p stack
• Messages are propagated through pubsub
• Finality exchange over libp2p streams
• Lotus feeds chain information into F3
• F3 has a way to bootstrap

(WIP)

Tasks

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1. Location of participants in Lotus stack, multiple identities in one instance #103
   +0
2. Implement finality decision exchange protocol #15
   fdex +1
   
3. GossipSub / Lotus Integration #225
   5 of 5
   Component integration +2
   
4. Bootstrap mechanism #270
   +0
   
5. Lotus feeds EC chain to F3 #271
   +0
   
6. Active participation and message signing APIs in Lotus #272
   +0
   
7. Expose F3 state in lotus API #365
   +0
   

[jennijuju]

@Kubuxu question for you - how would the application fetch the finality / get a signal from lotus that "we have reached finality for this epoch via 3"? Something new along with ChainHead (which only gives your the latest block w/o confirming it is finalized) ?

[Kubuxu]

I haven't thought about it a lot, but it seems reasonable, ChainGetFinalizedHead or something like that.

[Kubuxu]

PR in lotus: filecoin-project/lotus#12119
I aim to make it ready for review before Monday. I would appreciate reviews on Monday there.