Python wrapper needs updating for the cluster ids

[rambaut]

The output of jclusterfunk now emits a column node_id instead of node_number and parent_id instead of parent_number

'node_number'
  File "/cephfs/covid/bham/climb-covid19-ellabyn/.conda/envs/polecat/lib/python3.9/site-packages/polecat-1.0-py3.9.egg/polecat/scripts/Snakefile", line 68, in __rule_process_clusters
  File "/cephfs/covid/bham/climb-covid19-ellabyn/.conda/envs/polecat/lib/python3.9/concurrent/futures/thread.py", line 52, in run
Exiting because a job execution failed. Look above for error message
Exiting because a job execution failed. Look above for error message```

[rambaut]

Updated code. Needs testing.