nix: Add flatpak and more packages

nix/configuration.nix

@@ -131,6 +131,7 @@
       hunspell
       hunspellDicts.de_DE
       hunspellDicts.en_US
+      makemkv
     ];
   };
 
@@ -149,6 +150,10 @@
   environment.pathsToLink = [ "/share/nix-direnv" ];
   environment.shells = with pkgs; [ zsh ]; # adds zsh to /etc/shells
 
+  services.flatpak.enable = true;
+  xdg.portal.enable = true;
+  xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
+
   # List packages installed in system profile. To search, run:
   # $ nix search wget
   environment.systemPackages = with pkgs; [
@@ -184,8 +189,12 @@
     polkit_gnome
     nix-index
     python3
+    black
     libnotify
+#     unstable.tor-browser-bundle-bin
     killall
+    findutils
+    xorg.xkill
     unzip
     vlc
     direnv
@@ -193,6 +202,21 @@
     handbrake
     nmap
     jq
+    jdk
+    # emacsPackages.clang-format # formatting for java
+    gradle
+    maven
+    android-tools
+    dvdisaster
+    mate.engrampa
+    # toybox
+    unixtools.procps
+    qpdfview
+    ffmpeg
+    links2
+    julia-bin
+    xdg-desktop-portal-gtk
+    discord
   ];
 
   nixpkgs.overlays = [
@@ -212,7 +236,6 @@
     fira-code
     fira-code-symbols
     source-code-pro
-    xorg.xkill
   ];
 
   # Some programs need SUID wrappers, can be configured further or are