Add json-schema support

[yvan-sraka]

It would be nice to handle json-schema, few months ago, I played with this experiment:

{ pkgs ? import <nixpkgs> { }, data ? {
  # "productId" = 1;
  # "productName" = "A green door";
  # "price" = 12.5;
  # "tags" = [ "home" "green" ];
}, schema ? {
  # "$schema" = "https://json-schema.org/draft/2020-12/schema";
  # "$id" = "https://example.com/product.schema.json";
  # "title" = "Product";
  # "description" = "A product in the catalog";
  # "type" = "object";
} }:
with builtins;
let
  jsonData = pkgs.writeText "data.json" (toJSON data);
  jsonSchema = pkgs.writeText "schema.json" (toJSON schema);
  check = pkgs.runCommand "check-jsonschema" { } ''
    mkdir -p $out && echo 0 > $out/output
    ${pkgs.check-jsonschema}/bin/check-jsonschema --schemafile ${jsonSchema} ${jsonData} || echo $? > $out/output
  '';
  valid = readFile "${check}/output" == "0\n";
in valid # trace valid { }