wifi: add rbtree source and Run_context
wifi: cleanup driver main
wifi: add Run_queue to Routine
wifi: add blocking mutex implemenation
wifi: adapt signal handling

By now, instead of explizitly scheduling at various points, e.g. when
calling wake_up(), we add or remove routines to and from the run queue.

That enables us to block on mutex and in general schedule more like the
original Linux implementation.
wifi: adapt init.cc to latest changes