Deprecate Emergency, Alert, and Notice levels

:Release Notes:
Logs at levels of Emergency, Alert, and Notice will now generate
warnings that these levels have been deprecated.

:Detailed Notes:
Logging in webOS using the new API will be restricted to the following
levels: Debug, Info, Warning, Error, and Critical. The enumerants for
the remaining levels are now marked as deprecated so that any logs
using them will generate compile-time warnings.

At some point these deprecated enumerants will be deleted from the API.
This change should alert developers before that deletion causes the
build to be broken.

Internal warning messages generated as a result of the deprecation,
and otherwise unavoidable, have suppressed to give a clean compile of
PmLogLib itself.

:Testing Performed:
- Compiled some sample code using the deprecated levels and confirmed
the warnings were generated.
- Ensured that a local build succeeded (i.e. that no dependant
components had set -Werror).

:QA Notes:

:Issues Addressed:

[GF-7643] Unused pmloglib levels to be marked for deprecation

Open-webOS-DCO-1.0-Signed-off-by: Keith Derrick <keith.derrick@lge.com>

Change-Id: I16c9874ee9e0e4f52ca0c4dfdc57b068a300adf6
Reviewed-on: https://g2g.palm.com/2781
Reviewed-by: Build Verification
Reviewed-by: Keith Derrick <keith.derrick@lge.com>
Tested-by: Keith Derrick <keith.derrick@lge.com>
Reviewed-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>