Display worker versions without a revision

Depends backend#1624 (closed)
Refs https://redmine.teklia.com/issues/4471

When viewing worker versions on /process/workers, the frontend currently list versions using data mostly coming from revisions.

When the selected worker has no repository set, the display must be simplified and only display:

• the newly serialized version integer
• the newly serialized created date
• the worker version state