Shared libraries with C/C++ targets

[sgammon]

When building a Native Image as a shared library, users will want to make use of those outputs downstream, most obviously in cc_* targets.

The following would be great:

// imports...

native_image(
  name = "my-image",
  shared_library = True,
  // ...
)

cc_binary(
  name = "some-binary",
  deps = [
    ":my-image",
    // ...
  ],
  // ...
)

# bazel build //:some-binary

To support this, we'll need to ship providers with Native Image targets that build shared libraries, so that downstream rules can resolve the generated library and headers.

[sgammon]

part of #121

[sgammon]

It's unclear which providers we need to make this work seamlessly, but, for the moment, it's worth looking at transitive_native_libraries (part of the JavaInfo provider).