[PFW] Integrate PFW core version 3.2.6 release

PFW 3.2.6 release notes:
https://github.com/intel/parameter-framework/releases/tag/v3.2.6



This release contains the following changes:
- CMake: define installation components
- Enum parameter serialization fix in raw value space
- Version number guessing now prioritizes the ".version" file generated
by the "git archive" export and then falls back to the git revision
(opposite of what was done before).
- Some CMake modernization.

Bug: 124767636
Test: build

Change-Id: Ic55dfc09da3436d0a4182463fa44a4dd6a9bfb80
Signed-off-by: Sebastien Guiriec <sebastien.guiriec@renault.com>