add CopilotChat - seems advanced but simpler than others

lua/plugins/copilot.lua

@@ -0,0 +1,14 @@
+return {
+  {
+    'CopilotC-Nvim/CopilotChat.nvim',
+    dependencies = {
+      { 'github/copilot.vim' }, -- or zbirenbaum/copilot.lua
+      { 'nvim-lua/plenary.nvim', branch = 'master' }, -- for curl, log and async functions
+    },
+    build = 'make tiktoken', -- Only on MacOS or Linux
+    opts = {
+      -- See Configuration section for options
+    },
+    -- See Commands section for default commands if you want to lazy load on them
+  },
+}