USE_PMLOG lib cmake flag

:Release Notes:
Add PM_LOG lib cmake switch. By default pmloglib is enabled.

:Detailed Notes:
Allow to make choise of loggin system inside db8. This is usefull
for users, that doesn't have new pmloglib or whant to use internal db8
logging system. Also choise of logging system moved into .bb and build-desktop
files

:Testing Performed:

:QA Notes:

:Issues Addressed:

Open-webOS-DCO-1.0-Signed-off-by: Maksym Sditanov <maxim.sditanov@lge.com>

Change-Id: I08be86c8f9a744634f289e3ed50d41fe5427e7d2
Reviewed-on: https://g2g.palm.com/3193
Reviewed-by: Build Verification
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Roger Stringer <roger.stringer@lge.com>