CMakeLists: Enable USE_PMLOG flag

:Release Notes:
Turn on USE_PMLOG to enable logging using pmloglib's new functions
via the MojLog class.
Add PmLogLib detection to CMakeLists.txt

:Detailed Notes:

:Testing Performed:
 Tested on local environment

:QA Notes:

:Issues Addressed:
[GF-8150] ActivityManager: Conform to new PmLogLib specifications

Open-webOS-DCO-1.0-Signed-off-by: shrinivas.kulkarni <shrinivas.kulkarni@lge.com>

Change-Id: I7563fe3f15e2d252fca15fe5d6b782f5d1c3875b
Reviewed-on: https://g2g.palm.com/3014
Reviewed-by: Build Verification
Reviewed-by: Roger Stringer <roger.stringer@lge.com>
Tested-by: Roger Stringer <roger.stringer@lge.com>