outputs: Deprecate all unused outputs

I believe that people are either using disko through the flake or via
nixpkgs. In both cases, the `default.nix` file contains a lot of outputs
that are not needed.

Adding scary error messages with a call to action like this should help
confirm or deny this theory.

default.nix

@@ -15,9 +15,12 @@ let
       };
     };
   };
+  # We might instead reuse some of the deprecated output names to refer to the values the _cli* outputs currently do,
+  # but this warning allows us to get feedback from users early in case they have a use case we haven't considered.
+  warnDeprecated = name: lib.warn "the ${name} output is deprecated and will be removed, please open an issue if you're using it!";
 in
 {
-  lib = lib.warn "the .lib.lib output is deprecated" diskoLib;
+  lib = warnDeprecated ".lib.lib" diskoLib;
 
   _cliDestroy = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).destroy;
   _cliDestroyNoDeps = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).destroyNoDeps;
@@ -35,24 +38,24 @@ in
   _cliDestroyFormatMountNoDeps = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).destroyFormatMountNoDeps;
 
   # legacy aliases
-  create = cfg: builtins.trace "the create output is deprecated, use format instead" (eval cfg).config.disko.devices._create;
-  createScript = cfg: pkgs: builtins.trace "the create output is deprecated, use format instead" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScript;
-  createScriptNoDeps = cfg: pkgs: builtins.trace "the create output is deprecated, use format instead" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScriptNoDeps;
+  create = cfg: warnDeprecated "create" (eval cfg).config.disko.devices._create;
+  createScript = cfg: pkgs: warnDeprecated "createScript" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScript;
+  createScriptNoDeps = cfg: pkgs: warnDeprecated "createScriptNoDeps" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScriptNoDeps;
 
-  format = cfg: (eval cfg).config.disko.devices._create;
-  formatScript = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScript;
-  formatScriptNoDeps = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScriptNoDeps;
+  format = cfg: warnDeprecated "format" (eval cfg).config.disko.devices._create;
+  formatScript = cfg: pkgs: warnDeprecated "formatScript" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScript;
+  formatScriptNoDeps = cfg: pkgs: warnDeprecated "formatScriptNoDeps" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).formatScriptNoDeps;
 
-  mount = cfg: (eval cfg).config.disko.devices._mount;
-  mountScript = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).mountScript;
-  mountScriptNoDeps = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).mountScriptNoDeps;
+  mount = cfg: warnDeprecated "mount" (eval cfg).config.disko.devices._mount;
+  mountScript = cfg: pkgs: warnDeprecated "mountScript" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).mountScript;
+  mountScriptNoDeps = cfg: pkgs: warnDeprecated "mountScriptNoDeps" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).mountScriptNoDeps;
 
-  disko = cfg: (eval cfg).config.disko.devices._disko;
-  diskoScript = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).diskoScript;
-  diskoScriptNoDeps = cfg: pkgs: ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).diskoScriptNoDeps;
+  disko = cfg: warnDeprecated "disko" (eval cfg).config.disko.devices._disko;
+  diskoScript = cfg: pkgs: warnDeprecated "diskoScript" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).diskoScript;
+  diskoScriptNoDeps = cfg: pkgs: warnDeprecated "diskoScriptNoDeps" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).diskoScriptNoDeps;
 
   # we keep this old output for backwards compatibility
-  diskoNoDeps = cfg: pkgs: builtins.trace "the diskoNoDeps output is deprecated, please use disko instead" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).diskoScriptNoDeps;
+  diskoNoDeps = cfg: pkgs: warnDeprecated "diskoNoDeps" ((eval cfg).config.disko.devices._scripts { inherit pkgs checked; }).diskoScriptNoDeps;
 
   config = cfg: (eval cfg).config.disko.devices._config;
   packages = cfg: (eval cfg).config.disko.devices._packages;