genode_until_run can be called now with a spawn id to able to reattach to a
spawned process (amt, serial output). Run scripts can now call genode_until_run
multiple times.
This patch moves the os/config examples to their respective run scripts,
removes some of them, and moves the priority example to the src/init
directory (where other examples are located).
Additionally, this patch adapts the OKL4-specific priority.run test to
the recent changes of the timer interface.
