6083 documentation update native api examples dataset

[pkiraly]

What this PR does / why we need it: It improves the Native API documentation by providing full curl examples for some Dataset regaring calls.

Which issue(s) this PR closes: none of them. It is an additional step for solving #6083

Special notes for your reviewer: These commits continue a previous pull request which handles examples regarding dataverses. This one finishes the reformatting of dataverse API calls, and covers some of the dataset related calls. It does not covers all such calls, fearing that it is already too large request. The rest of dataset related API calls, and file related API call will be handled in different pull requests.

Suggestions on how to test this:

cd doc/sphinx-guides
make clean && make html
firefox build/html/api/native-api.html

Does this PR introduce a user interface change?: no

Is there a release notes update needed for this change?: no

Additional documentation: no

[coveralls]

Coverage remained the same at 19.47% when pulling bc6f37d on pkiraly:6083-documentation-update-native-API-examples-dataset into d0d4e24 on IQSS:develop.

[pkiraly]

This PR was developed by Göttingen eResearch Alliance, Germany, and funded by SSHOC, "Social Sciences and Humanities Open Cloud". SSHOC has received funding from the European Union’s Horizon 2020 project call H2020-INFRAEOSC-04-2018, grant agreement #823782.