Create aerie-schemas repo for JSON schemas

[dandelany]

Description

We have a growing collection of Aerie features which create or ingest specific formats of JSON data, and we should publish JSON schemas for all of these formats so users can understand them & build interfaces with other systems.

Requirements

• Create new aerie-schemas repo
• Include schemas for:
  • plan.json format (for plan import/export)
  • seq-json format
  • Simulation results format (TBD, for stateless aerie)
• Determine how & when we'll publish the schemas
  • npm and/or pip packages
  • Release updates as part of aerie-release process?
• Deprecate https://github.com/NASA-AMMOS/seq-json-schema (eventually)