Identify a deposit in the archive after loading

As a software author I want to find the deposit I made on HAL in the SWH archive so that I can reference my software publication with a persistent url

• return an identifier to the deposit client (so it will be on the client's web page)
• decide how the web-app resolves the identifier
  • archive.softwareheritage.org/browse/revision/?origin={,} open task #859 (closed) for web-view

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Migrated from T858 (view on Phabricator)