#9650 documenting the API call to list dataverses linked to a dataset

[pkiraly]

What this PR does / why we need it:

It provides a documentation to an API call, which is in the code base, but not documented. The documentation will be available at the admin/dataverses-datasets.html page.

Which issue(s) this PR closes:

It is a step towards closing #9650, but it does not close it completely, it is just a baby step.

Special notes for your reviewer:

Suggestions on how to test this:

cd doc/sphinx-guides/
source venv/bin/activate
make clean
make html
firefox build/html/admin/dataverses-datasets.html 

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

It modifies the documentation only.

Is there a release notes update needed for this change?:

Additional documentation:

Before:

After:

[kcondon]

@pkiraly There is a slight error in the example command -it should be a GET, not a PUT, or just remove -X PUT entirely:

curl -H "X-Dataverse-key: $API_TOKEN" http://$SERVER/api/datasets/$linked-dataset-id/links

[pkiraly]

@kcondon done