Add vendor snapshot modules

This implements four modules (static/shared/header libraries, and
binaries) for vendor snapshot. These modules will override source
modules if BOARD_VNDK_VERSION != current.

Bug: 65377115
Test: 1) VNDK_SNAPSHOT_BUILD_ARTIFACTS=true m dist vndk vendor-snapshot
Test: 2) install snapshot under source tree
Test: 3) set BOARD_VNDK_VERSION and boot cuttlefish
Change-Id: I24ddb4c3aa6abeab60bbfd31bcbd8753e2592dc5