unify overlays

We used to have overlay definitions in home/overlays and
packages/default. Let's unify them.
Using the exposed overlay from the flake required some changes in the
home-manager config though.

home/modules/packages.nix

@@ -1,123 +1,132 @@
 {
   pkgs,
+  lib,
   inputs,
   config,
   ...
 }:
 
-with pkgs;
 let
   cfg = config.schmittlauch.packages;
-  unstable = inputs.nixos-unstable.legacyPackages.${stdenv.hostPlatform.system};
-  nur = inputs.nur.legacyPackages.${stdenv.hostPlatform.system};
+  unstable = inputs.nixos-unstable.legacyPackages.${pkgs.stdenv.hostPlatform.system};
+  nur = inputs.nur.legacyPackages.${pkgs.stdenv.hostPlatform.system};
 
-  graphicsApps = [
-    inkscape
-    exiftool
-  ]
-  ++ (with gimp3Plugins; [
-    #fourier  # broken
-    #lqrPlugin  # broken
-  ])
-  ++ lib.optionals pkgs.stdenv.isLinux [
-    darktable
-    gimp3
-    hugin
-    #luminanceHDR  # FIXME, build failure
-    xournalpp
-  ]
-  ++ lib.optionals pkgs.stdenv.isDarwin [
-    gimp2
-  ];
+  graphicsApps =
+    with pkgs;
+    [
+      inkscape
+      exiftool
+    ]
+    ++ (with gimp3Plugins; [
+      #fourier  # broken
+      #lqrPlugin  # broken
+    ])
+    ++ lib.optionals pkgs.stdenv.isLinux [
+      darktable
+      gimp3
+      hugin
+      #luminanceHDR  # FIXME, build failure
+      xournalpp
+    ]
+    ++ lib.optionals pkgs.stdenv.isDarwin [
+      gimp2
+    ];
 
-  multimediaApps = [
-    mpv
-  ]
-  ++ lib.optionals pkgs.stdenv.isDarwin [ vlc-bin ]
-  ++ lib.optionals pkgs.stdenv.isLinux [
-    vlc
-    amarok
-    clementine
-    kdePackages.elisa
-    musescore
-    tenacity
-    #nur.repos.fooker.studio-link
-  ];
+  multimediaApps =
+    with pkgs;
+    [
+      mpv
+    ]
+    ++ lib.optionals pkgs.stdenv.isDarwin [ vlc-bin ]
+    ++ lib.optionals pkgs.stdenv.isLinux [
+      vlc
+      amarok
+      clementine
+      kdePackages.elisa
+      musescore
+      tenacity
+      #nur.repos.fooker.studio-link
+    ];
 
-  cliApps = [
-    coreutils
-    myVim
-    htop
-    tmux
-    httpie
-    rsync
-    ponysay
-    gti
-    tree
-    lsof
-    mosh
-    openssh
-    sshfs-fuse
-    sshuttle
-    cryfs
-    gnupg
-    unar
-    lzop
-    p7zip
-    pwgen
-    pandoc
-    pdfgrep
-    # zig dependency breaks occasionally, stay on C version for now
-    ncdu_1
-    dos2unix
-    unzip
-    fswatch
-    jq
-    age
-    lnav
-    spacer
+  cliApps =
+    with pkgs;
+    [
+      coreutils
+      myVim
+      htop
+      tmux
+      httpie
+      rsync
+      ponysay
+      gti
+      tree
+      lsof
+      mosh
+      openssh
+      sshfs-fuse
+      sshuttle
+      cryfs
+      gnupg
+      unar
+      lzop
+      p7zip
+      pwgen
+      pandoc
+      pdfgrep
+      # zig dependency breaks occasionally, stay on C version for now
+      ncdu_1
+      dos2unix
+      unzip
+      fswatch
+      jq
+      age
+      lnav
+      spacer
 
-    nix-output-monitor # putting this here as a plain `nix` alternative
-  ]
-  ++ lib.optionals pkgs.stdenv.isLinux [
-    xclip
-    smbnetfs # for FUSE smb mounting
-    psmisc # for killall
-    torsocks
-    agrep
-    reptyr # re-bind running program to other tty
-  ];
+      nix-output-monitor # putting this here as a plain `nix` alternative
 
-  nixHelpers = [
+    ]
+    ++ lib.optionals pkgs.stdenv.isLinux [
+      xclip
+      smbnetfs # for FUSE smb mounting
+      psmisc # for killall
+      torsocks
+      agrep
+      reptyr # re-bind running program to other tty
+    ];
+
+  nixHelpers = with pkgs; [
     nixpkgs-review
     nixfmt
     nix-top
     statix
   ];
-  devTools = [
-    curl
-    httpie
-    gcc
-    shellcheck
-    mtr
-    ripgrep
-    fd
-    pre-commit
-    scriv
+  devTools =
+    with pkgs;
+    [
+      curl
+      httpie
+      gcc
+      shellcheck
+      mtr
+      ripgrep
+      fd
+      pre-commit
+      scriv
 
-    # Haskell
-    ghc
-    cabal2nix
-  ]
-  ++ lib.optionals pkgs.stdenv.isLinux [
-    gdb
-    strace
-    ltrace
-    valgrind
-    zeal
-  ];
+      # Haskell
+      ghc
+      cabal2nix
+    ]
+    ++ lib.optionals pkgs.stdenv.isLinux [
+      gdb
+      strace
+      ltrace
+      valgrind
+      zeal
+    ];
 
-  pythonTools = with python3Packages; [
+  pythonTools = with pkgs.python3Packages; [
     python # to shadow old macOS python
     ipython
     uv
@@ -131,16 +140,16 @@ let
     mypy
   ];
 
-  games = [
+  games = with pkgs; [
     superTuxKart
     #hedgewars
   ];
 
-  desktopCommon = [
+  desktopCommon = with pkgs; [
     keepassxc
   ];
 
-  desktopLinux = [
+  desktopLinux = with pkgs; [
     firefox
     chromium
     kdePackages.falkon
@@ -187,31 +196,33 @@ let
     chromedriver
   ];
 
-  kdeTools = [
-    okteta
-  ]
-  ++ (with kdePackages; [
-    okular
-    gwenview
-    yakuake
-    dolphin
-    spectacle
-    kate
-    kleopatra
-    qdirstat
-    ark
-    kwalletmanager
-    #ktouch  # TODO: unbreak
-    kcharselect
-    konversation
-    krdc
-    skanlite
-    akonadiconsole
-    tokodon # mastodon client
-    networkmanager-qt
-    kcrash
-    breeze-gtk
-  ]);
+  kdeTools =
+    with pkgs;
+    [
+      okteta
+    ]
+    ++ (with kdePackages; [
+      okular
+      gwenview
+      yakuake
+      dolphin
+      spectacle
+      kate
+      kleopatra
+      qdirstat
+      ark
+      kwalletmanager
+      #ktouch  # TODO: unbreak
+      kcharselect
+      konversation
+      krdc
+      skanlite
+      akonadiconsole
+      tokodon # mastodon client
+      networkmanager-qt
+      kcrash
+      breeze-gtk
+    ]);
 in
 {
   options.schmittlauch.packages = {
@@ -248,7 +259,7 @@ in
       ++ (lib.optional cfg.kde kdeTools)
     );
 
-    nixpkgs.overlays = import ../overlays.nix;
+    nixpkgs.overlays = lib.attrValues inputs.self.overlays;
     nixpkgs.config = {
 
       permittedInsecurePackages = [