[IMPR] Show an error message and leave if script is not localized

If this script is not localized for a given site

• raise TranslationError in createReferenceSection()
• catch TranslationError in treat_page, print the error message and close the generator

Also ignore if referencesSections or placeBeforeSections is missing and
place the references section before interwiki links, categories, and
bottom templates in such case.

Bug: T362103
Change-Id: I308be486356ec86d8475a3b841e8c0f219643d40