Feature: #93835 - AddErrorForProperty function for AbstractValidator

See forge#93835


When validating Extbase models, it could be helpful to assign the encountered error to a certain property. This is already possible by using $this->result->forProperty($propertyPath)->addError($error);. This method however is cumbersome and requires knowledge about the result object. To ease the pain for developers, a convenience method addErrorForProperty is now available.

Use it like this in a validator class:

public function isValid(): void
   // validation
      // tstamp_of_now_as_errorcode


The new method enables developers adding custom error messages to validation results of properties in a convenient way.