Resolve #3266538 "Possibility to configure"

Closes #3266538

config/install/webform_spam_words.settings.yml

-spam_words:
-  - SEO
-  - 'Digital Marketing'
-  - 'Click Here'
-  - unsubscribe
-  - FREE
-  - trial
-spam_text_message: 'Unable to submit form. Please contact the site administrator, if the problem persists.'
-spam_field_name: message