Propose FIP to specify basic JSONRPC interface

[LesnyRumcajs]

Issue summary

Scope

• Propose additive iterations on a cross-client RPC specification through a set of FIPs enshrining existing conventions
• Initial scope will target 3 FIPs
  • V0 - Reference: https://github.com/filecoin-project/lotus/blob/master/documentation/en/api-v0-methods.md
  • V1 - Reference: https://github.com/filecoin-project/lotus/blob/master/documentation/en/api-v1-unstable-methods.md
  • Private Eth Methods

Other information and links

[ansermino]

See #4038.

The structure of this new issue seems more actionable to me. Perhaps there should be some consideration for OpenRPC?

[LesnyRumcajs]

I'll let @aatifsyed pronounce on the OpenRPC here.