[autoform] Support rendering additional fields by providing the renderer function to fieldOptions

[taefi]

Describe your motivation

As there is no such a property as customFields in AutoForm, fieldOptions was supposed to taking care of both replacing a field as well as rendering additional fields to the form. Without this, for adding one additional field, the user need to customize the whole form layout. Also, this can be helpful when dealing with DTOs and nested objects.

Describe the solution you'd like

Suggestion: If the property for a fieldOption doesn't match any of the existing data properties, it should be rendered as an extra field on the page.

Describe alternatives you've considered

No response

Additional context

No response