Make _cwl_demo work from batch job

[EmileSonneveld]

Running this graph on CDSE staging gives an error:

{
  "hello": {
    "process_id": "_cwl_demo",
    "arguments": {"name": "Saturn"},
    "result": true
  }
}

OpenEO batch job failed: ProcessUnsupportedException(status_code=400, code='ProcessUnsupported', message="Process with identifier '_cwl_demo' is not available in namespace 'None'.", id='no-request')

The InSAR tool might run more than 15min and would need to be done as a batch job.

[soxofaan]

what I think has to happen here:

• the openeo processes that wrap the CWL workflows (e.g. _cwl_demo) have to move to a custom_processes.py file in the correct deploy project (os_creodias_openeo_k8s in this case)
• make sure this file is available in the docker containers (e.g. as config map)
• set env var OPENEO_CUSTOM_PROCESSES to point to that file