JSON schemas for PMM YAML files

limitations:

• template variables not cased for specific default file
• template variables with keys are wildcarded
• "position" attribute has no validation
• "streaming" default has no validation
• search has no validation; just accepts string
• schedule has no validation; just accepts string

TODO: "list of coordinates"

• schema for collection yaml
• schema for metadata yaml
• schema for overlay yaml
• schema for template yaml

Notes: