Add log for app launch timing [GF-2589]

- Add "SYSMGR PERF: APP LAUNCHED" line for each app launch, which
  can be matched with the already existing SYSMGR PERF: STATE MAXIMIZED
  to determine the launch time in milliseconds.

Open-webOS-DCO-1.0-Signed-off-by: Eric Blade <eric.blade@palm.com>

Change-Id: If3f011d8dc0a3172adeae619f49fe3cd329908ba
Reviewed-on: https://g2g.palm.com/1750
Reviewed-by: Build Verification
Reviewed-by: Eric Blade <eric.blade@palm.com>
Tested-by: Eric Blade <eric.blade@palm.com>
Reviewed-by: Roger Stringer <roger.stringer@lge.com>