Clean up, improved commands, added cmd variables

- added dateDiff, for new $followage cmd variable
- added new domain structs for UserFollows response types

git fmt formatting fixes

[feature] Twitch command create, read impl

- implemented http adapter (REST interface)
- create, getAll, getOne works for twitch cmds
- cmd parsing works
- small subset of cmd variables supported

pre-release v0.8.1 - phillzbot (or jsonpbot v3)

- fairly good domain-driven inspired repo setup
- command package has twitch services and storage, discord stubs
- domain types and interfaces for twitch and discord
- twitch packge as a provider for IRC, Kraken/Helix APIs, and eventsub
  (eventually)
- mongodb/docdb singleton under infrastructure
- http adapter for rest api implemented (gorilla mux router)

close to something that can be deployed on aws!