Move documentation to GitHub

[MarkEWaite]

Move documentation to GitHub

• Migrate docs to GitHub
• Try different layout for image examples
• Use code formatting for syntax examples
• Remove the since statements
• Group methods with headings
• Add more method headings
• Hide the REST API documentation, not verified
• Another attempt to comment out a block
• Remove the REST description
• Shorter message to match
• Narrower example
• Updates and corrections in changelog
• Optimize images

Testing done

Confirmed that the documentation is no worse than the earlier documentation from the wiki. Many improvements are still possible and desirable, but this set of changes is a step forward.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes