Outsourcing of the duplicate checker

[ludwiglierhammer]

recordlinkage is too memory-intensive.
Replace it with splink.

• We should use the duplicate checker from marine_qc: implement duplicate checker from cdm_reader_mapper marine_qc#207.
• We plan to replace ``recordlinkagewithsplink`: Replace recordlinkage with splink marine_qc#210
• We should consider to use the duplicate checker directly in the GLAMOD marine processing scripts (see the quality control)