remove duplicates already provided by niphas

- Delete configs/bash.nix (identical to niphas, was dead code)
- Delete configs/direnv.nix (dead code, niphas provides direnv)
- Delete packages/vimv.nix (identical to niphas)
- Remove vimv from overlay and packages output
- Alias niveum-terminal/browser/filemanager to niphas equivalents
- Remove 17 duplicate packages from configs/packages.nix
- Remove nil from configs/editor.nix (niphas provides it)
- Remove dead dmenu packageOverride from configs/default.nix

packages/vimv.nix

@@ -1,27 +0,0 @@
-{
-  lib,
-  stdenv,
-  bash,
-  fetchFromGitHub,
-}:
-stdenv.mkDerivation {
-  name = "vimv";
-  src = fetchFromGitHub {
-    owner = "thameera";
-    repo = "vimv";
-    rev = "4152496c1946f68a13c648fb7e583ef23dac4eb8";
-    sha256 = "1fsrfx2gs6bqx7wk7pgcji2i2x4alqpsi66aif4kqvnpqfhcfzjd";
-  };
-  phases = [ "installPhase" ];
-  installPhase = ''
-    mkdir -p $out/bin
-    sed 's:#!/bin/bash:#!${bash}/bin/bash:' $src/vimv > $out/bin/vimv
-    chmod 755 $out/bin/vimv
-  '';
-  meta = with lib; {
-    homepage = "https://github.com/thameera/vimv";
-    description = "Batch-rename files using Vim";
-    license = licenses.mit;
-    platforms = platforms.all;
-  };
-}