Apply the navigation concept we have in the work packages module for the boards module:

* There is a Boards module in the sidebar
* Clicking on the label opens Begin of the insertionan index page with an overview of all boardsEnd of the insertion Begin of the deletion the default boardEnd of the deletion
* Clicking on the arrow opens the submenu without loading
* The submenu lists all available boards Begin of the deletion

**Open**

* How to handle "default boards"
* Proposal: There is always one "default board" per project
* A newly created board can not be made "default".
* The default board can be customized as any other boardEnd of the deletion