Metadata update should be its own event

[alainna]

Is your feature request related to a problem? Please describe. As a journal editor or preprints manager, I expect that updates to the metadata of an item (e.g. author's name, DOI) should be an event. Such event could be used by other features to trigger updates down the line e.g. to update Crossref DOI metadata.

Describe the solution you'd like

Updates to any article or preprint metadata should be an event, including eg:

• Title
• Journal Issue/No
• Author/editor name, affiliation, email address, ORCID iD
• DOI (preprint/published DOI)
• Abstract