refractor(opts): Move options into its own module

lua/symbols-outline/config.lua

@@ -0,0 +1,15 @@
+local vim = vim
+
+local M = {}
+
+local defaults = {
+    highlight_hovered_item = true,
+}
+
+M.options = {}
+
+function M.setup(options)
+   M.options = vim.tbl_deep_extend("force", {}, defaults, options or {})
+end
+
+return M