[3/4] Refactor: init: Use async | Move theme stuff to theme.lua

third commit of refactor

perf improvements due to async

run packer sync if base16 not found

this is not perfect error handling for initial run, but something

handle require errors

lua/theme.lua

@@ -0,0 +1,21 @@
+-- colorscheme related stuff
+vim.g.nvchad_theme = "onedark"
+
+local base16
+if
+    not pcall(
+        function()
+            base16 = require "base16"
+        end
+    )
+ then
+    return false
+else
+    base16(base16.themes["onedark"], true)
+    local cmd = vim.cmd
+
+    -- load bg color before async for smooth transition
+    local background = require("themes/" .. vim.g.nvchad_theme).black
+    vim.cmd("hi Normal guibg=" .. background)
+    return true
+end