Deprecate AFP in favor of the SMB variant

[mbentley]

The AFP variant of this image is no longer getting new features added. All new development is going into the SMB version.

1. Apple has already stated that AFP is no longer the default protocol as of the Mavericks release. SMB is now the default.

   SMB2
   SMB2 is the new default protocol for sharing files in OS X Mavericks. SMB2 is superfast,
   increases security, and improves Windows compatibility

2. In my own usage, SMB is much more stable than AFP for use with Time Machine as I regularly had to re-create my Time Machine backup from scratch with AFP but have never had to do so with SMB.

3. SMB support has been available from me since December 31, 2019 - 6444f17.