nodes.Apax retrain issues

[PythonFZ]

• no information that the training has been resumed from the train.log file
• the log.csv entries are purged when rerunning the Node.
• use self.state.restarted and bump minimum ZnTrack version to ensure that it can be handled:
  

  apax/apax/nodes/model.py

  Lines 92 to 93 in 4793205

  	ase.io.write(self.train_data_file, self.data)
  	ase.io.write(self.validation_data_file, self.validation_data)

• test that calling zntrack run apax.nodes.model.Apax --name Apax twice when the first run timed out / was killed yields the expected results
• adapt apax log level