openafs: Break into multiple packages with multiple outputs

Two packages:
- pkgs.linuxPackages.openafs (only kernel module)
- pkgs.openafs (client/server programs, manpages, docs)

Disable `ncurses` by default
- Only needed for debugging tools

Introduce but disable `tsmbac` by default
- IBM's on-site backup service called Tivoli Storage Manager Backup
  Client
- Make openafs ready to use tsmbac when supplied via local overlay
  (needs special patching)
- TSM is not in nixpkgs due to unclear/unfree licensing. (Binaries need
  to be modified to work with nixos)