Monitoring application wise background data usage.

Monitoring application wise background data usage.

Description: This patch updates logic to monitor application wise
background data usage.
When background data usage is notified, app_id will be appended with "_BACKGROUND".

Below is the test result performed using stc_test application.
=================================================================
 Main >> STC >> [Statistics] >> [Stats]
-----------------------------------------------------------------
 [  1] [Set] stats rule                                        >
 [  2] [Get] stats
 [  3] [Get] all stats
 [  4] [Get] total stats
 ---------------------------------------------------------------
 [ p ] Previous Menu
 [ m ] Show Menu
 [ q ] Quit
=================================================================
( 1354) >> 3
Success to set time interval
Success to request stats all info
( 1354) >> -----------------------------------------------------------------
App_id:   [org.tizen.browser]
Ifname:   []
Imsi:     [noneimsi]
Iftype:   [Undefined]
Received: [2182136]
Sent:     [102681]
Roaming:  [Unknown]
Protocol: [Unknown]
Process:  [Unknown]
From:     [0]
To:       [0]
-----------------------------------------------------------------
-----------------------------------------------------------------
App_id:   [org.tizen.browser_BACKGROUND]
Ifname:   []
Imsi:     [noneimsi]
Iftype:   [Undefined]
Received: [1872]
Sent:     [1872]
Roaming:  [Unknown]
Protocol: [Unknown]
Process:  [Unknown]
From:     [0]
To:       [0]
-----------------------------------------------------------------

Change-Id: Id8175494e559790e2959e5a6e7164de24e00a548
Signed-off-by: Nishant Chaprana <n.chaprana@samsung.com>