SDC-1148 Summary endpoints

These endpoints now work to retrieve the summmary ancillary dataproduct (used by to-be-defined service for copy to dcache).

https://sdc-dev.astron.nl:5554/atdb/get_summary/625124/json https://sdc-dev.astron.nl:5554/atdb/get_summary/625124/html https://sdc-dev.astron.nl:5554/atdb/get_summary/625124/pdf