add new BLE scan through android public API (upper than API level 21)

add new BLE scan through android public API (upper than API level 21)

since previous scan api - startLeScan() was deprecated in API level 21.
we should use startScan(List, ScanSettings, ScanCallback).
https://developer.android.com/reference/android/bluetooth/BluetoothAdapter.html

Change-Id: Ife58de26f1b132c260b94a6d0ba5c6aa17d1e7f3
Signed-off-by: jihwan.seo <jihwan.seo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17005
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>