Add setter and getter sensor handle attribute

Add setter and getter sensor handle attribute

Sensor handle attribute is diffrent with sensor listener attribute.
Listener attribute is depending on each listener, not sensor.
But handle attribute can affect all listeners connecting the sensor.

API function
-sensor_set_attribute_int : set sensor handle attribute
-sensor_get_attribute_int : get sensor handle attribute

Enumeration
-sensor_handle_attribute_e
  SENSOR_HANDLE_ATTR_PROXIMITY_SENSITIVITY_LEVEL :
    attribute of proximity sensor to control sensitivity level.
    the value should be sensor_proximity_sensitivity_level_e.

-sensor_proximity_sensitivity_level_e
  It can be used to set SENSOR_HANDLE_ATTR_PROXIMITY_SENSITIVITY_LEVEL.
  SENSOR_PROXIMITY_SENSITIVITY_LEVEL_WEAK : detects close distances.
  SENSOR_PROXIMITY_SENSITIVITY_LEVEL_MEDIUM : detects middle distances.
  SENSOR_PROXIMITY_SENSITIVITY_LEVEL_STRONG : detects long distances.

Change-Id: I6b736933b426c08fe93ee605587d25984a60b79b
Signed-off-by: TaeminYeom <taemin.yeom@samsung.com>