Harmonize embedded tarball name and unpacked directory names

We have some situations where the embedded download returns a filename like 4.1.3-196-g434f7c8.tgz which doesn't have a leading mongo-embedded-sdk on it. When unpacked, the directory does look right: mongo-embedded-sdk-4.1.3-196-g434f7c8.

There are probably some other inconsistencies. We should go through all the artifacts and download links and ensure that the filenames consistently are prefixed with mongo-embedded-sdk-$VERSION, and that they unpack into an analagously named directory. Similar checks should be done for the -latest download links.