Fix get device by name in device database store

A client should be able to query a device by UUID or name.

Currently this is simply broken as the code that searches with the name does also use the key _id.

https://code.fbi.h-da.de/danet/gosdn/-/blob/develop/controller/nucleus/databaseDeviceStore.go#L37

A solution could be to check if ID or Name is set in the Query object and only query for this option.