... not just only urn:jio: ones

The background story:

While editing instance parameters schemas for ERP5 SR, I used a modified version of https://microsoft.github.io/monaco-editor/playground.html#extending-language-services-configure-json-defaults to "visualize" the result of the json schema.

I tried to update it to integrate RJS_json_form to make a "two way editor", something similar to https://mozilla-services.github.io/react-jsonschema-form/ , the current state is https://codepen.io/jerome-nexedi/pen/dgwGRM (it's using with rjs_json_form verion 9dafc5c3 )

Now I have one problem that resolveExternalReference is called only for urn:jio: URLs, but I guess it would be nice that it's called for all URLs. I tried this attached patch, but it's still not good, because the URL is relative to the gadget URL, ie . it receives https://softinst93095.host.vifib.net/public/rjs_json_form/instance-kumofs-schema.json and not just ../instance-kumofs-schema.json

How about:

• delegating all external references to resolveExternalReference like started here ?
• making resolveExternalReference receive the reference as relative, "as-is in the schema", ie for this ./instance-kumofs-schema.json ref, resolveExternalReference would receive "./instance-kumofs-schema.json" ?

/cc @vpelletier @romain @vincentB

PS: the monaco json service also seem to have a problem here, I think it can resolve relative references like ./instance-kumofs-schema.json but not like ../caucase/instance-caucase-input-schema.json. That's why I had to do getSchema in that codepen.

PPS: there's no easier way to use renderjs on codepen ? or https://codesandbox.io/ ?