Issue #3040790 by Pancho: FillPdfFormForm::validateForm() throws exception when used programmatically

Issue #3038922 by Pancho: Split Webform tests to their own class, removing own uploadNodeImage() implementation

I guess a couple things were removed from the Webform schema or something.

Issue #2839942 by pianomansam: Users with Publish all PDFs permission also need Administer PDFs permission

Issue #2828240 by pianomansam: BaseFieldDefinitions in FillPdfFormField are missing required "weight" display option

Issue #2713013 by FatherShawn, wizonesolutions, pianomansam: PHP message: Recoverable fatal error: Argument 1 passed to Drupal\Core\Entity\ContentEntityForm::__construct()

Also removed an unused public variable (we have a static function
somewhere doing the job).

Issue #2828227 by pianomansam: Default entity ID isn't required, but is assumed by FillPdfLinkManipulator

Fix fails along the way and create a config schema so that I can test
properly.