Add documentation for JSON schema generation and observer map APIs

[janechu]

Pull Request

📖 Description

This change adds a document describing the JSON schema generated from path syntax of templates as well as the implementation of Observer Maps.

✅ Checklist

General

• I have included a change request file using $ npm run change
• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

[KingOfTac]

A lot to process but looks good to me.