Merge changes I2e5e7b51,I77914112,I8936d9d1,I63c8cf4f,I0a02eb43, ...

* changes:
  gn2bp: properly forward genrule dependency
  gn2bp: remove script from sources
  gn2bp: fix script location
  gn2bp: do not skip //buildtools and buildflag generation
  gn2bp: override deps before soong target is created
  gn2bp: start adding some verbose logging
  gn2bp: ignore copy targets in create_modules_from_target
  gn2bp: add basic action support
  gn2bp: explicitly make tool_files a list
  gn2bp: add basic parser support for copy and action_foreach rules
  gn2bp: allow targets to depend on chromium's libc++ and libunwind