Add AID for Virtual Machines

Add a new AID for Virtual Machines so we can grant
capabilities such as CAP_SYS_NICE.

Bug: 322197421
Test: Build and boots, and verified capabilities

Change-Id: Ie893ba8ed6956a554bccfbd00e4e6fe9212ea77d
Signed-off-by: David Dai <davidai@google.com>