Move Aurorae documentation to develop.kde.org

Documentation for creating window decorations with Auroare is currently on TechBase: https://techbase.kde.org/User:Mgraesslin/Aurorae

This makes it less obvious to find with other theming tutorials present at develop.kde.org, and from what I understood the plan is to progressively move everything over from TechBase anyway.

Is it okay if I just copy the contents of that page into a new section of https://develop.kde.org/docs/extend/plasma/?