Apply centralized nice script

:Release Notes:
Apply centralized nice script

:Detailed Notes:
In order to improve UX, we need to adjust nice values of system services.
Below services are important so we need to give more priority.
- Rendering services
- Media services
- Core services

:Testing Performed:

:QA Notes:

:Issues Addressed:
[GF-36804] Adjust NICE values for important processes

Open-webOS-DCO-1.0-Signed-off-by: Sangwoo Kang <sangwoo82.kang@lge.com>

Change-Id: I1012de9c82e18f47f84730cf1a5cf2c3578e5508
Reviewed-on: https://g2g.palm.com/3393
Reviewed-by: Build Verification
Reviewed-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Tested-by: Sangwoo Kang <sangwoo82.kang@lge.com>
Reviewed-by: Keith Derrick <keith.derrick@lge.com>