feat: Split config for colorscheme

lua/user/colorscheme.lua

@@ -0,0 +1 @@
+return "astrodark"

lua/user/init.lua

@@ -1,5 +1,4 @@
 return {
-  colorscheme = "astrodark",
   -- This function is run last and is a good place to configuring
   -- augroups/autocommands and custom filetypes also this just pure lua so
   -- anything that doesn't fit in the normal config locations above can go here