Add simulate-device-(dis)appeared CDM shell commands

Add 'companiondevice simulate-device-appeared' and
'companiondevice simulate-device-disappeared' Shell commands to be used
in CompanionDeviceManager tests.

Bug: 218615198
Test: atest CtsCompanionDeviceManagerCoreTestCases
Test: atest
  CtsCompanionDeviceManagerCoreTestCases:ObservingDevicePresenceTest
Change-Id: I5dad0b1859f5292fc0db68ca6ce2114eaa889d4e
Merged-In: I5dad0b1859f5292fc0db68ca6ce2114eaa889d4e