[Feature Request] json-like / json-is functionality

[ugexe]

Add json-like and json-is which would work like json but for parsing individual parts of a json structure.

    test-given '/foo', {
        test post(json => { :param<XXX>, }),
            status => 201,
            json-like => "/query-datetime" => /^\d\d\d\dT\d\d.*/,
            json-is => "/data/0/name" => "XXX";
    }