Minimal post-processing step

[led02]

• Provide deposition result for later steps using the cache
• Feed back information from deposition result ... somewhere

[sdruskat]

Thanks @led02!

Looks good to me so far.

I've changed to use the default YAML loader instead of CLoader in b88367b and re-worked CFF updating quite a bit in 51fd2bb. Please review carefully!

Notes on CFF updating:

• CFF doesn't (yet) have DataCite-like relations for identifiers, so this will append rather than re-write the new identifier to a (perhaps already existing) list of identifiers. I refrained from doing too much string diffing to detect previous versions, etc. This can be re-worked and made much better once CFF has the relations between identifiers implemented.
• Like I said, identifier overwrites are switched off now.
• The identifier description has been updated to include the version number from the deposit metadata, so that human users (for whom the description is) know what they are looking at. Ideally, we'd remove identifiers for older versions, but this isn't easily doable now without extra calls to the Invenio API.

[sdruskat]

Suggested change

	'description': "Generated by hermes after deposition.",
	'description': f"DOI for the published version {deposition['metadata']['version']} [generated by hermes]",

polish: Better describe the value of the identifier, use square brackets for easier data mining later.

[sdruskat]

@zyzzyxdonta Please feel free to give this a quick review as well.

[poikilotherm]

We have seen in the showcase testing this addition is very valuable and works without flaws so far. Ship it!