nix: Add basic neovim config

This should eventually replace the old .vimrc.

flake.nix

@@ -80,6 +80,39 @@
                 fade-in = 1;
               };
             };
+            programs.neovim = {
+              enable = true;
+              plugins = with pkgs.vimPlugins; [{
+                plugin = nvim-tree-lua;
+                type = "lua";
+                config = ''
+                  vim.g.loaded_netrw = 1
+                  vim.g.loaded_netrwPlugin = 1
+                  vim.opt.termguicolors = true
+                  require("nvim-tree").setup()
+                '';
+              }
+              {
+                plugin = indent-blankline-nvim;
+                type = "lua";
+                config = ''
+                  vim.cmd [[highlight IndentBlanklineIndent1 guibg=#1f1f1f gui=nocombine]]
+                  vim.cmd [[highlight IndentBlanklineIndent2 guibg=#1a1a1a gui=nocombine]]
+                  require("indent_blankline").setup {
+                    char = "",
+                    char_highlight_list = {
+                        "IndentBlanklineIndent1",
+                        "IndentBlanklineIndent2",
+                    },
+                    space_char_highlight_list = {
+                        "IndentBlanklineIndent1",
+                        "IndentBlanklineIndent2",
+                    },
+                    show_trailing_blankline_indent = false,
+                  }
+                '';
+              }];
+            };
             editorconfig = {
               enable = true;
               settings = {