fix: request the schema id URL instead of the current page url

[mmcorrelo]

When the schema id is defined with an URL should use that hostname to request the references, instead of using the current page URL

EXAMPLE:

{
	"$schema": "http://json-schema.org/draft-07/schema#",
	"$id": "https://resourse.example.com/schemas/resources/main.json#",
	"title": "This is my main schema",
	"description": "This is my main schema description.",
        "type": "object",
	"properties": {
	  "$ref": "/schemas/resources/version1.0.1.json#"
	}
  }

Currently, if the dereference work is being done locally at http://localhost:3000 the deref request will be done with URL http://localhost:3000/schemas/resources/version.1.0.1.json instead of https://resourse.example.com/schemas/resources/version1.0.1.json

This is related to this issue

[philsturgeon]

@Relequestual hey could I bother you for a quick check here? The issue is outlined in #199 and we want to make sure the case is even valid before merging this.

[philsturgeon]

@mmcorrelo hey, sorry for being quiet on this, but it's come up a few times in conversations and I'd like to progress with it. Can you take the time to write some tests so we can see the change in behavior?