Bulk Edit: Changes are applied very slowly, one by one

[sleidig]

If selecting many records to change a value using the "Bulk Edit" feature, saving/applying the changes takes a long time. Records are updated one by one. Maybe we can do a bulk write to the database instead (EntityMapperService.saveAll).

• Also, we may need a progress indication that informs the user this is still being applied.

[MalteHD]

As we observed today, the issue may also effect the deletion process.