Added UI for plugin system and upnp example

- Added wip UI for plugin tag system
- Added upnp port forwarder plugin
- Added error and fatal printout for plugins
- Optimized UI flow for plugin context window
- Added dev web server for plugin development purpose

example/plugins/upnp/mod/zoraxy_plugin/README.txt

@@ -0,0 +1,19 @@
+# Zoraxy Plugin
+
+## Overview
+This module serves as a template for building your own plugins for the Zoraxy Reverse Proxy. By copying this module to your plugin mod folder, you can create a new plugin with the necessary structure and components.
+
+## Instructions
+
+1. **Copy the Module:**
+    - Copy the entire `zoraxy_plugin` module to your plugin mod folder.
+
+2. **Include the Structure:**
+    - Ensure that you maintain the directory structure and file organization as provided in this module.
+
+3. **Modify as Needed:**
+    - Customize the copied module to implement the desired functionality for your plugin.
+
+## Directory Structure
+ zoraxy_plugin: Handle -introspect and -configuration process required for plugin loading and startup
+ embed_webserver: Handle embeded web server routing and injecting csrf token to your plugin served UI pages