Re-organize Logging.h to handle undef USE_PMLOG

:Release Notes:
Fix issue when project configured with -DUSE_PMLOG:BOOL=FALSE and when
configured with Qt version lower than 5.0.

:Detailed Notes:
- Re-organized Logging.h to separate Qt-related stuff and PmLog
- Added stubs for PMLOG_TRACE for situation when PMLOG is disabled.

Note: probably we should drop support for pmloglib-less build or we
shouldn't use PMLOG_TRACE and friends directly in code without any
guards.

:Testing Performed:
Desktop build with -DUSE_PMLOG:BOOL=TRUE and with FALSE.

:QA Notes:

:Issues Addressed:
[GF-41271] LunaSysService is logging debug messages at info level.

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Change-Id: I14e6e873f0a6c25e153ff9643555a1d19833c5ed
Reviewed-on: https://g2g.palm.com/3742
Reviewed-by: Build Verification
Reviewed-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Tested-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>