BibWorkflow: API updates
- The way run a workflow in a task queue has changed from a task_queue parameter into seperate "delayed" functions, such as start_delayed() or continue_oai_delayed().
- Adds custom kwargs to be passed to all workflow API functions that will be put into the workflow engine's extra_data column. This allows one to access this data from the workflow tasks.
- Documentation improved and corrected overall. Especially in bibworkflow_api.
- Updated worker plugins and unit tests to reflect these new changes.
- Renames several functions from camelCase to underscore_case.
- Renames Holding Pen template files from bibholdingpen_* to bibworkflow_* as well as other restructu.
- Adds a custom exception in bibworkflow_worker_engine instead of raising ValueError.
- Changes worker API names.
- Removes references to external_save as it is no longer used.
- Various fixes to the Holding Pen, improving PEP8 etc.
- Fixes many kwalitee issues.
- Adds Redis backend functionality, by Wojciech Ziolek.
Co-authored-by: Wojciech Ziolek <wojciech.ziolek@cern.ch>