show metadatalist of duplicate matches

[floriangantner]

References

Add references/links to any related issues or PRs. These may include:

• Fixes #60

Description

for every matching objects show the values defined in metadatalist. To improve the reason why the matching duplicates are shown only matching metadatafields are shown wich appear in the external-source object as well as in the matching object

Instructions for Reviewers

• import some entry which is already in the system and contains unambigious metadata (e.g. dc.identifier.doi)
• since 2023.02.00 the duplicates are shown in the import list.
• provided no tests yet

List of changes in this PR:

• print the available additional metadata from duplicates
  • the label of the metadata in the configuration can be translated
• filter the available metadatalist based on the existence of metadatafields in the external source entry as well as in the duplicate match
  • helps reasoning why it is some duplicate

Checklist

• [x] My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• [x] My PR passes ESLint validation using yarn lint
• [ ] My PR doesn't introduce circular dependencies (verified via yarn check-circ-deps)
• [ ] My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• [ ] My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• [ ] If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• [ ] If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• [x] If my PR fixes an issue ticket, I've linked them together.