Convert to standard CLI11 argument parser

This simplifies the argument parsing logic drastically and still
provides the same error handling as before.

Tested:
    Ran through unit test suite and manually verified that the command
    line functions as expected on a real BMC.

Change-Id: Ic5d69adf5359f9f64f2ada17e6a8f3242ca03e25
Signed-off-by: William A. Kennington III <wak@google.com>
8 files changed