Strip off seconds from strings.
Prepare code to easily provide a structured data to allow integrators to
format timing differently.
Provide a method to easily check if an opening hour is only valid for a
single day.
Relates: #10185
DayOfWeek is an enum as defined at https://schema.org/DayOfWeek
We missed the PublicHolidays enum value when building
`getDaysOfWeekWithMondayFirstWeekDay()` which is used in templates to
get ordered result.
Opening hours for public holidays were not rendered, which is now fixed.
That's necessary as models grow.
Added features should be tested to not break with future changes.
The tests revealed an existing error in fallback which got fixed to make
new test pass.
Relates: #18
Allows to import entity of type TouristAttraction.
Right now only in German, as this is most important.
Add output of tourist attraction via custom content element.
