Add function for standard structure returned by the API

The following structure is returned among many endpoints:

```r
structure(
    list(
      error = resp %>% chuck("error"),
      status = resp %>% chuck("status"),
      meta = resp %>% chuck("meta"),
      i18n = resp %>% chuck("i18n")
    ),
    class = "rigma_get_image_fills"
  )
```

Write a function to avoid code repetition.  