Create lightweight GUI version

This PR integrates changes that create a lighter GUI for the Fibernavigator.

Some rarely used features are now hidden by default. No functionnality was actually removed from the code, it is only hidden from the lightweight GUI.

Some GUI elements were also realigned, to get a cleaner interface.

The light GUI is now the default one. To choose which one to use, set the BUILD_LIGHTWEIGHT_GUI variable in the CMake. It is in the advanced section.