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

configs/editor.nix

@@ -38,7 +38,6 @@
     pkgs.pyright
     pkgs.haskellPackages.haskell-language-server
     pkgs.texlab
-    pkgs.nil
     pkgs.gopls
     pkgs.nixfmt-rfc-style
     pkgs.rust-analyzer