[R] Move Windows GCS dependency building upstream

On ARROW-16510, I added the GCS filesystem to the arrow PKGBUILD, bundling it in the arrow build. A better solution would be to put google-cloud-cpp in rtools-packages so we don't have to build it every time.

There is no google-cloud-cpp in https://github.com/msys2/MINGW-packages, so either we'd have to make one up for rtools-packages, or we use the bundled google-cloud-cpp in our cmake and see if we can put as many of its dependencies in rtools-packages to ease the build. Either way, we'd want to start by adding its dependencies.

https://github.com/msys2/MINGW-packages/tree/master/mingw-w64-nlohmann-json exists in MINGW-packages and could be brought over, but I don't think it's a big deal if it is bundled.

https://github.com/msys2/MINGW-packages/blob/master/mingw-w64-abseil-cpp/PKGBUILD exists and could be brought over, but note that it uses C+17. That doesn't seem to be a hard requirement, at least for what we're using, since we're building it with C+11.