VTS: Create vts-core suite and packaging rules

For migrating most existing VTS test to executable by Base TradeFed, we have to
create vts-core suite and test all of the modules in vts-core first.
And add the packaging rules for vts-core suite.

Bug: 137921421
Test: (1) add test_suites: ["vts-core"], to any module or patch aosp/1089570
      (2) $ m vts-core
      (3) check this module in the vts-core.zip

Change-Id: I7a52b3ee400f58e6c383638396ced7194d6bc65d