Define CI/CD process and workflow

[anweiss]

Using this as a starting point for discussion on a CI/CD workflow for automated testing and artifact generation/deployment. Initial thoughts below:

• [ ] Define high-level overview of CI/CD process and include this as part of a CONTRIBUTING.md or BUILD.md file
• [ ] Determine which items could be rolled up under automated testing
  • Validation of OSCAL-formatted XML against XSD/RNC
  • Validation of OSCAL-formatted XML against Schematron
  • Validation of OSCAL-formatted JSON against JSON schema
• [ ] Determine which items could be rolled up under automated artifact generation
  • Conversion of RNC to XSD via Trang
  • Conversion of non-OSCAL XML to OSCAL-formatted XML artifacts via XProc and Calabash
  • Conversion of OSCAL-formatted XML to JSON
• [ ] Determine who/what is responsible for automated artifact generation (e.g. CI/CD system vs. individual who executes automated tools locally and manually creates PRs with auto-generated artifacts)
• [ ] Select a CI/CD system (e.g. Travis CI, CircleCI, etc)

[anweiss]

Licensing as well. 18F example -> https://18f.gsa.gov/open-source-policy/

[david-waltermire]

Added user story #133 to address this.