urlResolver support for absolute paths

[misha-kotov]

As a Magento Developer, I want urlResolver to support absolute paths in addition to relative so that it's easier for me to pass it URLs without performing additional formatting.

This story is only for the input of the urlResolver query. The output fields will be corrected in the scope of #80

Acceptance Criteria:

• urlResolver accepts absolute and relative URLs as input (relative urls already work today)
• Changes are covered with web API functional tests. See \Magento\GraphQl\Catalog\ProductViewTest::testQueryAllFieldsSimpleProduct as an example.

[misha-kotov]

@naydav @pfantini I updated the description and AC to make this more clear. Let me know if there are any more outstanding questions here.

[naydav]

@misha-kotov

So for example, if we have a request

{
  urlResolver(url:"privacy-policy-cookie-restriction-mode")
  {
   id
   relative_url
   absolute_url 
   type
  }
}

Result should be

{
  "data": {
    "urlResolver": {
      "id": 4,
      "relative_url": "cms/page/view/page_id/4",
      "absolute_url": "http://graphql.local/index.php/cms/page/view/page_id/4",
      "type": "CMS_PAGE"
    }
  }
}

Correct?
But in such a case, I can not get a target_path

[misha-kotov]

This story is about the input only. User should be able to pass an absolute url to the resolver as input and get a valid response:

{
  urlResolver(url:"http://magento23.mk/privacy-policy-cookie-restriction-mode/")
  {

[naydav]

#398