battery: Divide "display_changed" plugin interface

battery: Divide "display_changed" plugin interface

In battery notificaion plugin, there was a function "display_changed"
used as a getter and setter duplicated about display state in
mobile and wearable battery plugin.
To divide the role of getting and setting display state
and they can be used in common devices, it is moved to core.

The role of setting display state in battery moudle is included in
new function "handle_display_state_changed", and it calls plugin interface
"launch_health_popup_by_display_state".

Previous "display_changed" is deleted from mobile battery plugin.
In wearable, the role of "display_changed" is moved to new function
"launch_health_popup_by_display_state". And it consists of the action
when display state is changed.

Change-Id: I1f63502ba36f10fcf93c99987c9ce132295397aa
Signed-off-by: TaeminYeom <taemin.yeom@samsung.com>