Add help linking to jsonschema/rjsf docs for JSON editor fields

- [ ] Link to jsonschema website for the collection schema JSON editor (even better if we find some online JSON schema builder, maybe the [formbuilder](https://github.com/Kinto/formbuilder/)?)
- [ ] Link to [uiSchema documentation](https://github.com/mozilla-services/react-jsonschema-form#the-uischema-object) for the collection uiSchema JSON editor

Locate the collection schema JSON editor and the collection uiSchema JSON editor in the repository. Add a link to the JSON Schema website for the schema editor and a link to the referenced uiSchema documentation for the uiSchema editor, then verify both links work in the interface.

Written by the indexing model from the issue text.