monitor: add cli11 argument parsing

Replace our custom argument parser with one from CLIUtils.

This results in a number of minor behavioral differences.
- The -? option is no longer recognized as

monitor: add cli11 argument parsing

Replace our custom argument parser with one from CLIUtils.

This results in a number of minor behavioral differences.
- The -? option is no longer recognized as an alias for -h/--help.
- The original parser returned EXIT_FAILURE in all cases, but CLIUtils
uses different non-zero error codes in different situations.
- Minor changes to help text descriptions:
----new----
Usage: build/phosphor-unit-failure-monitor.new [OPTIONS]

Options:
-h,--help Print this help message and exit
-s,--source TEXT REQUIRED
-t,--target TEXT REQUIRED
-a,--action ENUM:value in {start->0,stop->1} OR {0,1} REQUIRED

----old----
Usage: build/phosphor-unit-failure-monitor [options]
Options:
--help Print this menu
--source=<source> The source unit to monitor
--target=<target> The target unit to start or stop
--action=<action> Target unit action - start or stop

- The original parser displays the full help text on error, CLIUtils
does not:

----new----
$ phosphor-unit-failure-monitor
--source is required
Run with --help for more information.

----old----
$ phosphor-unit-failure-monitor
ERROR: Source not specified
Usage: build/phosphor-unit-failure-monitor [options]
Options:
--help Print this menu
--source=<source> The source unit to monitor
--target=<target> The target unit to start or stop
--action=<action> Target unit action - start or stop

Change-Id: I2417d9c857c6d8fc04807fe4729d2fa154e746a3
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>

show more ...