Introduce project-navigation (#140)
A project should be able to serve as a master project for several sub-project.
a sub-project navigation should be included top left above the project name.
Implementation
- add a trac.ini config option, which points to the file
- option is inherited by the further project
or
- the navigation should be included from the ../projnav.html location.
- Projnav wiki file is generated to ../projnav.html