Changed:

• 🔥 OcrdPage as proxy of PcGtsType instead of alias; also contains etree and mapping now
• 🔥 Processor.zip_input_files now can throw ocrd.NonUniqueInputFile and ocrd.MissingInputFile
  (the latter only if OCRD_MISSING_INPUT=ABORT)
• 🔥 Processor.zip_input_files does not by default use require_first anymore
  (so the first file in any input file tuple per page can be None as well)
• 🔥 no more Workspace.overwrite_mode, merely delegate to OCRD_EXISTING_OUTPUT=OVERWRITE
• 🎨 improve on docs result for ocrd_utils.config

Added:

• 👉 OCRD_DOWNLOAD_INPUT for whether input files should be downloaded before processing
• 👉 OCRD_MISSING_INPUT for how to handle missing input files (SKIP or ABORT)
• 👉 OCRD_MISSING_OUTPUT for how to handle processing failures (SKIP or ABORT or COPY)
  the latter behaves like ocrd-dummy for the failed page(s)
• 👉 OCRD_EXISTING_OUTPUT for how to handle existing output files (SKIP or ABORT or OVERWRITE)
• new CLI option --debug as short-hand for ABORT choices above
• Processor.logger set up by constructor already (for re-use by processor implementors)
• default-expand and validate ocrd_tool.json in Processor constructor, log invalidities
• handle JSON deprecation in ocrd_tool.json by reporting warnings