feat: config refresh

The goal of this commit was to break my config into smaller, logical
chunks. I was having a hard time remembering which file contained which
plugin config.

I also took the time to clean out some plugins I added but never used,
and add an old favourite (tpope/vim-surround).

lua/plugins/ui.lua

@@ -141,15 +141,4 @@ return {
 			alpha.setup(dashboard.opts)
 		end,
 	},
-	{
-		"akinsho/toggleterm.nvim",
-		opts = {},
-		keys = {
-			{
-				"<leader>T",
-				"<cmd>ToggleTerm direction=float<CR>",
-				desc = "Open floating terminal",
-			},
-		},
-	},
 }