This allows to fetch merged opening hours instead of actually edited
opening hours.
They will be merged per valid time span.
The data structure is a bit different as each time span has a list of
week days, each with its own open and end.
Relates: #10246
- Removed individual converters for TYPO3.
Conversion is now handled in a single converter.
- The new converter will import necessary dependencies upfront, e.g.
town or organisation.
- Move import state into extra class.
Relates: #34
