Tidying up and improving package

[richardreeve]

• Include authors without ORCIDs in codemeta.json and .zenodo.json
• Handle missing ORCID and ROR records without crashing
• Fail on connection errors and unexpected HTTP statuses, writing no files so everything is left in its original state
• Add optional top-level Project.toml keys description, keywords, category, development_status and publications as the source for codemeta.json and .zenodo.json, backfilling them from codemeta.json when absent
• Split the source into separate files and export crosswalk, increase_patch, increase_minor, increase_major
• Construct a missing author_details section in Project.toml from the authors field and codemeta.json or .zenodo.json when consistent with authors