Delete serials

Serials shouldshould, neverin most cases, not be deleted.

The only exception to thisexceptions are duplicates of serials. This happens when serials are create through different sources.sources without all information.

 When this happens, both serials should be checked and their data need to be synced (warranty, calibration intervals, fielfile manager.manager contents...)

After syncing theall serial data, the serial with existing stock transactions should be retained,  while the duplicate can be deleted.

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