conf: Parse 'ForegroundAppList' property of process.conf

conf: Parse 'ForegroundAppList' property of process.conf

Parse configuration for foreground status app(s)
which want to have low oom_socre_adj

This configuration supports recording low oom_score_adj
for foreground app. oom_score_adj is an important indicator
to choose victim when available memory is too low.
Therefore, with this configuration, specific foreground app(s) have low
probability to be choosen as victim of LMK.

A new configuration called 'App' in section 'ForegroundAppList'
is added in process.conf

Change-Id: Ia25c4a966ad7351e0bf67b55d8fb925417f1cc8c
Signed-off-by: Unsung Lee <unsung.lee@samsung.com>