add a command to restart kakpipe fifo

In workflows we have the necessity to restart the fifo and the command running inside (whatever its state could be: running or stopped).

1. Add kakpipe-restart command that works only on fifo buffer if an option kakpipe_argument is defined
2. Add a buffer scoped variable kakpipe_arguments to save the arguments given to kakpipe that triggered the creation of the buffer
3. Add a scoped alias restart in the fifo buffer to close the actual buffer and restart a new one with the saved kakpipe arguments