Add new appOps to track the behavior of VPN app

OPSTR_USE_VPN_SERVICE is used for tracking VPN app which uses
VpnService.
OPSTR_USE_VPN_MANAGER is used for tracking VPN app which uses
VpnManager.

Bug: 197135981
Test: TH
Change-Id: Idaa262623440c178caf346bca76a72b673235850