Keep only one coherence workflow

[clausmichele]

We currently have many different coherence workflows, which is due to the latest developments (parameters refinement, parallel execution etc.). Since the one in use is stable and work well, we could remove the old ones to avoid confusion.

[clausmichele]

We should:

• Remove from cwl folder: sar_coherence.cwl sar_coherence_parallel.cwl
• Rename sar_coherence_parallel_temporal_extent.cwl to sar_coherence.cwl
• Remove from sar folder: sar_coherence.py
• Rename sar_coherence_parallel.py to sar_coherence.py and replace all the occurrencies
• Re-build the image and replace it in the CWL files
• Change the url of the CWL used in the openEO process: https://github.com/Open-EO/openeo-geotrellis-kubernetes/blob/b41a78191d6ce3e2420ad04a3e048631d2d634cd/openeo-geopyspark-k8s-custom-processes/src/openeo_geopyspark_k8s_custom_processes/custom_processes.py#L292

@EmileSonneveld we should plan this together to avoid breaking things. All the changes will be done within the repository refactor, I will open a PR which will include the changes.

[clausmichele]

WIP here: #108