[6/X] Introduce CompanionDevicePresenceMonitor

Add CompanionDevicePresenceMonitor which uses and combines
information it receives from BleCompanionDeviceScanner and
BluetoothCompanionDeviceConnectionListener, and provides a simple
interface to CompanionDeviceManagerService.

Bug: 211398735
Test: atest CtsCompanionDeviceManagerCoreTestCases
Test: atest CtsCompanionDeviceManagerUiAutomationTestCases
Test: atest CtsOsTestCases:CompanionDeviceManagerTest
Change-Id: I9da3d34a6d2bb27f0f75dfa9341d95c37922fff2