Restrict access from apps to bluetooth_address setting

BluetoothManagerService for some reason leaks the Android's Bluetooth
MAC address via Settings.Secure which is normally readable by all
apps. This lets apps bypass the restriction on access to Bluetooth MAC
address from apps.

This commit fixes the issue by restricting access to bluetooth_address
secure setting (Settings.Secure). Only packages which hold the
android.permission.LOCAL_MAC_ADDRESS permission retain access.

This commit accordingly grants LOCAL_MAC_ADDRESS permission to the
system Shell app because a number of scripts (including Android CTS)
use "adb shell settings get secure bluetooth_address" as a convenient
way to query the device's Bluetooth MAC address over ADB. This is
acceptable because the user of the device can see the Bluetooth MAC
address and thus it's fine for shell to be able to see the address as
well.

Test: See CTS test added in the cts project in this topic.
Test: "adb shell settings get secure bluetooth_address" returns the
      Bluetooth MAC address of the Android.
Test: "adb shell settings list secure | grep bluetooth_address"
      returns the Bluetooth MAC address of the Android.
Test: Bluetooth works (toggling off/on, pairing, file transfer)
Bug: 33701414

Change-Id: I17b110b96eb3794b25c1661e93d29a7a003e3c9a