Add apex.use_vndk_as_stable property

Vendor APEXes(in general, APEXes for non-system partitions) which is
supposed to be tied to a specific VNDK version can set this new property
so that it excludes VNDK libs and use them from VNDK APEX (provided by
system parition).

For these APEXes to use VNDK libs from VNDK APEX, linkerconfig should
link "vndk" linker namespace to the namespaces of these APEXes.

Bug: 159195575
Test: m (soong test added)
Change-Id: If90650973239ef7aab0ff084488bda57d9b0364e