Change AWS C++ SDK (extension) to download the SDK tarball instead of git clone

I am experiencing hard times with Github's operational performance - dramatically low bandwidth (tens of KB/s instead of, at least, few MB/s).

Additionally to this - it would be good to see the progress of nested operations, during the build process.

https://github.com/apache/nifi-minifi-cpp/blob/ddddb22d63c4a60b97066e555f771135c8dbb26d/cmake/BundledAwsSdkCpp.cmake seems to be related.
I was surprised when the console's stdout has nothing to show about the progress of the cloning process.

Ivan