Implement a classical navigation bar (#85)
The navigation-bar should construct itself, mainly based on the hierarchy defined with the construct provided within #2
Tasks:
- Create a Component within tracx
- copy relevant resource-files to tracx (java-script-menu, css etc.)
- create a *.css extensions for trac
- modify the layout.html to include the menu
- retrieve a static menue from a file
- autogenerate this menue-file from trac (change-listener)