Add nyx-cmd support for calling Led APIs and alarm, suspend System APIs

:Release Notes:
Add nyx-cmd support for calling the Led APIs and the alarm and suspend
APIs of the System module.

:Detailed Notes:
nyx-cmd now has support for calling the following Nyx APIs:
- Led set_brightness
- Led get_brightness
- System set_alarm
- System query_next_alarm
- System query_rtc_time
- System system_suspend

:Testing Performed:
Tested options with nyx-cmd from command line

:QA Notes:

:Issues Addressed:
[CTO-724] Modify nyx-cmd to support Led APIs
[CTO-542] Extend nyx-cmd to support the alarm and suspend APIs of the
          System module

Open-webOS-DCO-1.0-Signed-off-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Change-Id: I84653bea3a41fbe244c9d08cd497ee3eddc22167
Reviewed-on: https://g2g.lgsvl.com/6482
Reviewed-by: DCO Verification
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Tested-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Reviewed-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Change the argument to set_alarm command

:Release Notes:

:Detailed Notes:
Since specifying that the alarm should be set to some number of
seconds in the future is the more likely use case than wanting to
specify an absolute time, the argument has been modified accorfingly.

:Testing Performed:
Verified the alarm is fired after the given number of seconds.

:QA Notes:

:Issues Addressed:
[CTO-878] Change the argument to the set_alarm nyx-cmd command
          to be the number of seconds from now

Open-webOS-DCO-1.0-Signed-off-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Change-Id: Iae62bbb1180361982b1408dd649caed1164185ad
Reviewed-on: https://g2g.lgsvl.com/6505
Reviewed-by: DCO Verification
Reviewed-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Tested-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Merge branch 'develop'