support for file methods

[bnomei]

it seems page and field methods do work but custom file methods from plugins do not.

[bnomei]

'fileMethods' => [
        'myurl' => function () {
            return $this->url();
        },
    ],

{
  "query": "page",
  "select": {
    "image": "page.images.first.myurl"
  }
}

[bnomei]

would be great so i can use my srcset plugin

{
  "query": "page",
  "select": {
    "image": "page.images.first.lazysrcset('default')"
  }
}

[bnomei]

like discussed on slack this would need some kind of whitelist. actually the page and fields method work in my case because of an different issue #11.

[bastianallgeier]

✅