Move streamcontroller out of common programs to nixy specific.

nodes/hosts/common/programs/streamcontroller.nix

@@ -1,8 +0,0 @@
-{ pkgs, ... }: {
-  # List packages installed in system profile. To search, run:
-  # $ nix search wget
-  environment.systemPackages = [
-    pkgs.streamcontroller
-  ];
-}
-