usertools: replace optparse with argparse

usertools: replace optparse with argparse

The optparse module is deprecated and replaced with new argparse.
Using the python standard argument parser instead of C library
style getopt gives a number of advantages such as checking
for conflicting arguments, restricting choices, and automatically
generating help messages.

Some of the help messages are now less wordy.

The code now enforces the rule that only one of the pmdinfo formats
can be specified: raw or json.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>