Docs/integrate with main docs

[w4bremer]

📑 Description

Integrate the template documentation with the main docs at apigear.io

✅ Checks

• [ ] My pull request adheres to the code style of this project
• [ ] My code requires changes to the documentation
• [ ] I have updated the documentation as required
• [x] All the tests have passed

ℹ Additional Information

[w4bremer]

Only unrelated tests to the docs changes have failed.