Broad-based local development setup architecture

[Shadowfiend]

We need to fully articulate and capture how we expect Keep local development to occur. This requires:

• Documenting the setup of a full local environment with multiple nodes, chain, etc.
• Documenting how we expect day-to-day local dev to happen for the team---e.g., with a cloud deployment of components that aren't changing, or with a local kube cluster, or whatever else.
• Building out any local scripts to aid in the above.
• Documenting the role of pkg/chain/local and pkg/net/local implementations in local development.