Add an option not to install all VNDK libs

When using VNDK snapshot, current VNDK libs are not required. Use
"TARGET_SKIP_CURRENT_VNDK=true" to skip installing current VNDK libs.

Bug: 123607022
Test: TARGET_SKIP_CURRENT_VNDK=true PRODUCT_EXTRA_VNDK_VERSIONS=28 m -j
Change-Id: I65c902c71a7952536bbf824a1dccb9360e843f1a