Add guide for annotating IAMC format scenario data #167

[f-innatech]

Added a section on annotating long-term scenario data in IAMC format, including challenges and examples for mapping to OEO terms.

Summary of the discussion

Addition to course 05 #167

Type of change (CHANGELOG.md)

Added

• Add a new class (#)

Updated

• Update a definition (#)

Removed

• Remove a broken link (#)

Workflow checklist

Automation

Closes #

PR-Assignee

• [ ] 🐙 Follow the workflow in CONTRIBUTING.md
• [ ] 📝 Update the CHANGELOG.md
• [ ] 🐙 Assign a reviewer to the PR

Reviewer

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