None of the existing ironic-python-agent integer config options included
min or max values. Added appropriate min/max values for the integer
config options.
Two of the integer options are for ports (listen_port and
advertise_port). These were changed to use the more appropriate
oslo_config cfg.PortOpt instead of cfg.IntOpt. PortOpt has the proper
min and max values built in.
Change-Id: I98709a45d099aea62c9973beb6817591cb445a9c
Story: 1731950