[FEAT] Allow importing and translation of common metadata standards

[jsheunis]

If some entity is already described with a common metadata standard and available to be fetched from an online API, the user interface should support fetching said metadata and translating it into datalad-concepts-based RDF, for use in the application. A common example for researchers would be if some data or researcher articles have already been published under a DOI online, then they should be able to enter the DOI, click "Fetch metadata", and then all metadata returned from whichever endpoint should be made available in the app. This implies:

• some common functionality to support fetching metadata from an API
• functionality to support translating common metadata standards into datalad-concepts-based linked metadata

A starting point could be fetching basic DOI metadata from doi.org, for which a basic implementation has already been demonstrated in datalad-catalog, see: https://github.com/datalad/datalad-catalog/blob/c911350089617e47fd480b443b9869a830e5a1f2/datalad_catalog/catalog/assets/app_component_dataset.js#L904