[EPIC] Gordian Core Interfaces (UX? Docs? Launch?)

[jackzampolin]

A key part of gordian is the ability to easily modify subsystems to suit the need of the application. This feature is enabled by the design of the codebase with a focus on modularity. In order to help kickstart external contributions and reduce friction for new users we should:

1. Have an explainer doc with all the core interfaces and their functions w/in the codebase. Audience for this doc is developers either implementing gordian in their SDK app (i.e. explains how to compose the different interfaces) or developers looking to implement these interfaces.

• MarshalCodec - tm/tmcodec/codec.go
• ConsensusStrategy - tm/tmconsensus/consensusstrategy.go
• ConsensusHandler - tm/tmconsensus/handler.go
• HashScheme - tm/tmconsensus/hashscheme.go
• SignatureScheme - tm/tmconsensus/signaturescheme.go
• TimeoutStrategy - tm/tmengine/timeoutstrategy.go
• gossip.Strategy - tm/tmgossip/strategy.go
• network.Connection - tm/tmp2p/network.go`
• network.ConsensusBroadcaster - tm/tmp2p/network.go
• ActionStore - tm/tmstore/actionstore.go
• BlockStrore - tm/tmstore/blockstore.go
• FinalizationStore - tm/tmstore/finalizationstore.go
• MirrorStore - tm/tmstore/mirrorstore.go
• RoundStore - tm/tmstore/roundstore.go
• ValidatorStore - tm/tmstore/validatorstore.go
• MerkleScheme - gmerkle/merkle.go
• Signer - gcrypto/signer.go
• PubKey - gcrypto/pubkey.go
• CommonMessageSignatureProof - gcrypto/commonmessagesignatureproof.go

2. List all existing implementations for these interfaces and ideas for future work. Ideally this points out which interface implementations are "production" ready and/or "help wanted". We should also write issues for each help wanted with pointers on how to get started on that particular interface. (cc @jpb, @beckettsean)

3. Have a single example of how to implement the crypto signer interfaces in rust using a grpc serivce

[jackzampolin]

Lets make these docs in godocs