Context:

See parent ticket. This refactoring will be split into two parts: part 1 to adjust the current DistributedBy field to allow for distributed by Variable and date reports and part 2 to move this DistributedBy field from the ReportConfiguration to the ReportData.

This ticket is to take care of Part 1: refactor the current distributed by field in the report config.

AT:

• The config field `DistributedBy` is changed to no longer just reflect the DistributedBy field but to be a dto that contains respective ValueDtos for the distributedBy reports (details see parent ticket)
• Existing reports are migrated
• Documentation is updated