Export the headers of stub libraries

Create a target with the headers presented to ModuleLibApi surface. The
top level @api_surfaces repository will contain an alias to this header
target.

This creates some duplication since the relevant CcInfo can be retrieved from
the targets created by the expansion of
cc_stub_suite -> cc_library_static -> ... macros. But creating a new
target explicitly ensures that the alias in @api_surfaces does not get
broken due to any internal refactoring of these macros

Test: b cquery
//frameworks/native/opengl/libs:libEGL_stub_libs_module-libapi_headers
--config=android --output=starlark
--starlark:expr="providers(target)['CcInfo'].compilation_context.includes"
depset(["frameworks/native/opengl/include",
"bazel-out/aosp_cf_arm64_phone-userdebug-opt/bin/frameworks/native/opengl/include",
"frameworks/native/opengl/libs/EGL/include",
"bazel-out/aosp_cf_arm64_phone-userdebug-opt/bin/frameworks/native/opengl/libs/EGL/include"])

Change-Id: I2271d9254948b7d588b4c0017bc0550d8314aed3