[neovim] replace neo-tree with snacks.nvim

Replace neo-tree.nvim with snacks.nvim for file explorer functionality and
remove several other plugins including:
- mini-animate
- mini-starter
- indent-blankline

The snacks.nvim plugin provides better file explorer, dashboard, indentation
guides, and other UI improvements in a more cohesive package.

Also removed the large file autocommand as snacks.nvim handles this with its
bigfile module.

.config/nvim/lua/plugins/illuminate.lua

@@ -6,7 +6,7 @@ require("illuminate").configure({
 		"avante",
 		"lspsagafinder",
 		"mason",
-		"neo-tree",
+		"snacks_picker_list",
 		"packer",
 		"starter",
 	},