Combine rm with apt-get install, use fingerprint for extra security since it cannot be MITM'd

So we grab the key and add the apt sources before the `ENV` version to help with docker caching.  We use the key fingerprint to provide a layer of security to the images. Moved the `rm` so that it is in the same layer as the `update` and can be actually removed rather than just a whiteout layer and still taking up space.

Feel free to apply it to the rest of the versions or I can update this PR as well.