Define JSON schema for the warehouse's config.json and validate it

[imrehg]

Describe the feature request

Define a JSON schema and add validator for the config.json used by the warehouse loader.

Affected product area (please put an X in all the brackets that apply)

[ ] Documentation
[ ] Data access
[x] Infrastructure
[x] Loader pipeline
[ ] Other (please describe)

Additional context

This would allow the warehouse loader to validate a schema that is being loaded or a tool to check things before they are uploaded to the storing bucket.