Added support for ComputeSegmentIndexFile worker job

[hotzenklotz]

This PR adds support for triggering the ComputeSegmentIndexFile worker job through a REST route. This is very similar to the the ComputeMeshFile job.

UI Changes:

• A button to trigger this worker job for superusers
• Proper listings on the jobs page

URL of deployed dev instance (used for testing):

• https://___.webknossos.xyz

Steps to test:

Use the button (only visible for superusers) or send a POST request (needs auth cookie), e.g.:

curl 'http://localhost:9000/api/jobs/run/computeSegmentIndexFile/sample_organization/Sample_e2006_wkw?layerName=segmentation&mag=64-64-64' \
  -X 'POST' \
  -H 'Content-Length: 0' \
  -H 'Cookie: id=1-12345678' \
  -H 'Origin: http://localhost:9000' \
  -H 'Referer: http://localhost:9000/datasets/sample_organization/Sample_e2006_wkw/view' \
  -H 'Sec-Fetch-Dest: empty' \
  -H 'Sec-Fetch-Mode: cors' \
  -H 'Sec-Fetch-Site: same-origin' \
  -H 'accept: application/json' \

TODOs:

• Job listing in the UI requires some love. Alternatively, hide this entry altogether.

Issues:

• related to https://github.com/scalableminds/voxelytics/pull/3390

---

(Please delete unneeded items, merge only when none are left open)

• Updated changelog
• Updated migration guide if applicable
• Updated documentation if applicable
• Adapted wk-libs python client if relevant API parts change
• Removed dev-only changes like prints and application.conf edits
• Considered common edge cases
• Needs datastore update after deployment

[hotzenklotz]

Somewhat unrelated change, but the indentation for this was one level too deep.

[hotzenklotz]

@philippotto Can you please have a quick look at the frontend changes. NO need to deep test this with the worker running. Thanks.

[philippotto]

the front-end looks good to me 👍