feat(flix): move to own config, add indexing and menu script

configs/flix.nix

@@ -0,0 +1,41 @@
+{ config, pkgs, ... }:
+let flixLocation = "/media/flix";
+in {
+  fileSystems.${flixLocation} = {
+    device = "prism.r:/export";
+    fsType = "nfs";
+  };
+
+  systemd.user.services.flix-index = {
+    description = "Flix indexing service";
+    after = [ "network.target" ];
+    wantedBy = [ "default.target" ];
+    script = ''
+      cachedir="${config.users.users.me.home}/.cache"
+      flix_cache="$cachedir/flix_index"
+
+      [ -d "$cachedir" ] || mkdir -p "$cachedir"
+
+      find ${flixLocation} -type f > "$flix_cache"
+    '';
+    startAt = "hourly";
+    serviceConfig = {
+      Type = "oneshot";
+      User = config.users.users.me.name;
+    };
+  };
+
+  environment.systemPackages = [
+    (pkgs.writeDashBin "flixmenu" ''
+      set -efu
+      cachedir="${config.users.users.me.home}/.cache"
+      flix_cache="$cachedir/flix_index"
+
+      [ -f "$flix_cache" ] || exit 1
+
+      ${pkgs.dmenu}/bin/dmenu -i -p flix -l 5 < "$flix_cache" \
+        | ${pkgs.findutils}/bin/xargs -I '{}' ${pkgs.xdg_utils}/bin/xdg-open '{}'
+    '')
+  ];
+
+}