Cleanup and refactor YamlFormSubmissionForm

Problem

The YamlFormSubmissionForm is getting too complex. The code should be refactored to make sure this form in maintainable and allow for future improvements including paging.

Notes

• Should move anything logic that is not specific to the form outside the class.
  • \Drupal\yamlform\YamlFormSubmissionForm::replaceTokens
  • \Drupal\yamlform\YamlFormSubmissionForm::displayMessage
  • \Drupal\yamlform\YamlFormSubmissionForm::displayAdminAccessOnlyMessage
• Move all message into one place.
• Review automated and manual tests

• YamlFormSubmissionForm::isGet()
• YamlFormSubmissionForm::isRouteName($route_name)
• Prefix all actions with word action actionSave(). actionComplete()

Refactoring

• Move all generic logic from YamlFormSubmissionForm to generic form independant services
• YamlFormSubmissionFormMessages
• YamlFormSubmissionFormInputs
• YamlFormSubmissionFormLimits

Development Notes

• Branch Name: 2712447-yaml-form-refactor-submission-form
• Patch Name:yaml-form-refactor-submission-form-2712447-XX.patch
• Commit message: Issue #2712447: Cleanup and refactor YamlFormSubmissionForm