add some plugins and keymaps

lua/custom/plugins/nvim-tree.lua

@@ -0,0 +1,15 @@
+-- recommended for nvim-tree
+vim.g.loaded_netrw = 1
+vim.g.loaded_netrwPlugin = 1
+
+return {
+	"nvim-tree/nvim-tree.lua",
+	version = "*",
+	lazy = false,
+	dependencies = {
+		"nvim-tree/nvim-web-devicons",
+	},
+	config = function()
+		require("nvim-tree").setup {}
+	end,
+}