Improve OpenAPI documentation grouping

[tomi-rli]

Summary of the discussion

Describe the findings of the discussion in the issue or meeting.

Type of change (CHANGELOG.md)

Features

• Add OpenAPI schema, Swagger UI .

Changes

• Group API endpoints into clearer functional categories
• Improve the OpenAPI documentation of dataset endpoints with summaries, parameters, responses and request examples.

Bugs

• Fixed a problem with
  (#)

Removed

• Remove a broken link
  (#)

Documentation updates

• Updated documentation for
  (#)

Workflow checklist

Automation

Closes #

PR-Assignee

• 🐙 Follow the workflow in
  CONTRIBUTING.md
• 📝 Update the
  CHANGELOG.md
• 📙 Update the documentation on
  mkdocs

Reviewer

• 🐙 Follow the
  Reviewer Guidelines
• 🐙 Provided feedback and show sufficient appreciation for the work done