Route for adding OME-Zarr datasets directly

[normanrz]

Detailed Description

Currently, we have the explore route but it requires a roundtrip to the frontend for the dataset to be imported. For integrations with other tools, we need a route that imports a dataset directly into Webknossos.
If logged in, the route should put the dataset in the user's organization. Alternatively, we should think of another token-based authentication mechanism for app-to-app communication.

Context

• Specific to long-running jobs (set jobsEnabled=true in application.conf)
• Specific to webknossos.org (set isDemoInstance=true in application.conf)