pktgen: add sample script pktgen_sample01_simple.sh

pktgen: add sample script pktgen_sample01_simple.sh

Add the first basic pktgen samples script pktgen_sample01_simple.sh,
which demonstrates the a simple use of the helper functions.
Removing pktgen.conf-1-1 as that example should be covered now.

The naming scheme pktgen_sampleNN, where NN is a number, should encourage
reading the samples in a specific order.

Script cause pktgen sending with a single thread and single interface,
and introduce flow variation via random UDP source port.

Usage example and help:
 ./pktgen_sample01_simple.sh -i eth4 -m 00:1B:21:3C:9D:F8 -d 192.168.8.2

Usage: ./pktgen_sample01_simple.sh [-vx] -i ethX
  -i : ($DEV)       output interface/device (required)
  -s : ($PKT_SIZE)  packet size
  -d : ($DEST_IP)   destination IP
  -m : ($DST_MAC)   destination MAC-addr
  -c : ($SKB_CLONE) SKB clones send before alloc new SKB
  -v : ($VERBOSE)   verbose
  -x : ($DEBUG)     debug

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>