Remove other now obsolete nix files

project/build.nix

@@ -1,35 +0,0 @@
-let
-  nixpkgs = builtins.fetchTarball {
-    #url = "https://github.com/NixOS/nixpkgs/archive/92e990a8d6bc35f1089c76dd8ba68b78da90da59.tar.gz";
-    url = "channel:nixos-23.05";
-  };
-  pkgs = import nixpkgs {};
-  initScript = pkgs.writeScript "docspell-build-init" ''
-    export LD_LIBRARY_PATH=
-    ${pkgs.bash}/bin/bash -c "sbt -mem 4096 -java-home ${pkgs.openjdk17}/lib/openjdk"
-  '';
-in
-  with pkgs;
-    buildFHSUserEnv {
-      name = "docspell-sbt";
-      targetPkgs = pkgs:
-        with pkgs; [
-          netcat
-          jdk17
-          wget
-          which
-          dpkg
-          sbt
-          git
-          elmPackages.elm
-          ncurses
-          fakeroot
-          mc
-          zola
-          yarn
-
-          # haskells http client needs this (to download elm packages)
-          iana-etc
-        ];
-      runScript = initScript;
-    }