Fix #4210: Remove builderDefs

This was one of the ways to build packages, we are trying
hard to minimize different ways so it's easier for newcomers
to learn only one way.

This also:

- removes texLive (old), fixes #14807
- removed upstream-updater, if that code is still used it should be in
  separate repo
- changes a few packages like gitit/mit-scheme to use new texlive

nixos/modules/services/misc/gitit.nix

@@ -663,7 +663,7 @@ in
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
       path = with pkgs; [ curl ]
-             ++ optional cfg.pdfExport texLiveFull
+             ++ optional cfg.pdfExport texlive.combined.scheme-basic
 	     ++ optional (cfg.repositoryType == "darcs") darcs
 	     ++ optional (cfg.repositoryType == "mercurial") mercurial
 	     ++ optional (cfg.repositoryType == "git") git;