Feature: #80187 - Add the "Confirmation" finisher to the form editor

See forge#80187

Description

The "Confirmation Message" finisher is now editable through the form editor. The "Confirmation Message" finisher is now able to render a content element as message. The option "contentElementUid" can be used to render a content element:

finishers:
  -
    identifier: Confirmation
    options:
      contentElementUid: 765

If contentElementUid is set, the option "message" will be ignored.

The option "typoscriptObjectPath" can be used to render the content element through a typoscript lib (default: 'lib.tx_form.contentElementRendering')

finishers:
  -
    identifier: Confirmation
    options:
      contentElementUid: 765
      typoscriptObjectPath: 'lib.tx_myext.customContentElementRendering'

Impact

The "Confirmation Message" finisher is now editable through the form editor. The "Confirmation Message" finisher is now able to render a content element as message.