Use Webform as Module Config Page?
The Webform module just extends Drupal's Form API. Most of the elements available to a webform can be used in custom-built forms. For example, you can use the WebformMultiple element in any FAPI form. 

@see https://git.drupalcode.org/project/webform/blob/8.x-5.x/src/Element/WebformMultiple.php