HotwordDetectionSrvc: Handle SoundTrigger permissions in VIMS

This allows properly checking/noting against the voice interactor or
HotwordDetectionService as needed. Otherwise,
SoundTriggerMiddlewarePermission notes ops for data delivery to the
interactor, even if the data only reaches the HotwordDetectionService.

This is accomplished with a decorator for permission checks, that wraps
the real implementation. A proxy that serves as the remote Binder object
is also needed, to allow this decoration pattern.

The list of sessions stored in VIMS is removed for simplicity. It
currently serves no purpose (used only in dump() but doesn't implement
it so it's a no-op there).

DataDelivery checks will be addressed in a followup change.

Bug: 186164881
Test: manual - permissions are checked appropriately
Test: atest CtsVoiceInteractionTestCases
Change-Id: I80dabaf6ae0e781028dde16ead3321fbff319542