layouts: Prefer capital eszett over double S as German capitalization

The ezsett character didn't have a capitalization in fonts for long time and thus double S was used instead. Since some years a proper unicode capitalization is available and can be used instead (see https://en.wikipedia.org/wiki/%C3%9F#Development_of_a_capital_form). Prefer the new capital eszett but still offer the double S as second alternative.