Implement datetime/format preferred hour format for the locale (j)

- Also finish to implement hour (h, H, k, K) by removing the TODO, because
  interpretation never changes. The rules (see TODO in diff) are meant for the
  entity that defines the skeleton data.
Use cldr.supplemental.weekData according to cldr#0.2.0

- s/cldr.supplemental.firstDay()/cldr.supplemental.weekData.firstDay();
- s/cldr.supplemental.minDays()/cldr.supplemental.weekData.minDays();
Update rxaviers/cldr dependency to 0.2.0