update(FHC Color Themes): makes the css variables and color modes configurable through the config for different fh's

application/config/theme.php

@@ -0,0 +1,10 @@
+<?php
+
+if (! defined('BASEPATH')) exit('No direct script access allowed');
+
+
+// changing the color theme
+
+$config['theme_name']='default';
+$config['theme_css']= "public/css/theme/default.css";
+$config['theme_modes']=['light','dark'];