ofproto: Support packet_outs in bundles.

ofproto: Support packet_outs in bundles.

Add support for OFPT_PACKET_OUT messages in bundles.

While ovs-ofctl already has a packet-out command, we did not have a
string parser for it, as the parsing was done directly from command
line arguments.

This patch adds the string parser for packet-out messages, adds
support for it into the 'ovs-ofctl packet-out' command, and adds a new
ofctl/packet-out ovs-appctl command that can be used when ovs-ofctl is
used as a flow monitor.  The old 'ovs-ofctl packet-out syntax is
deprecated' and will be removed in a later OVS release.

The new packet-out parser is further supported with the ovs-ofctl
bundle command, which allows bundles to mix flow mods, group mods and
packet-out messages.  Also the packet-outs in bundles are only
executed if the whole bundle is successful.  A failing packet-out
translation may also make the whole bundle to fail.

Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>