Move Academy into the documentation

[dg-concordium]

To improve maintainability and reuse of content, move Academy into the documentation.

Sub-tasks

• Move content, including images
• Update brand identity https://drive.google.com/drive/folders/1EEKCFfhWo7LkSC3BQbXoRhWUgFwmBEbJ
• Set up documentation to do the build
• Publish

Add label for component and priority.