Shimmy shimmy WTF functions polyfill

Copy the plugin to plugins/frdl/publicPages/zzzzzzzz_wtf wtf this MUST run as LAST publicPages Plugin!

In short:

I definitely do NOT like worpress code. This SHOULD be a reason we MUST shim it to the OIDplus core!

Inspired by

• https://github.com/Badcow/Shortcodes
• https://github.com/voku/PHP-Hooks/

https://gist.github.com/wehowski/d16a4ce9cdeb5da1e90f9a7b28b6ffdb#file-plugin-php

The additional plugins Plugin (this one) is searching for pluginfiles in:

• userdata/plugins/{vendor}/{plugintype}/{pluginname}/wtf-plugin.php
• userdata/{tenantdir}/{vendor}/{plugintype}/{pluginname}/wtf-plugin.php
• plugins/{vendor}/{plugintype}/{pluginname}/wtf-plugin.php <--- Old/regular Plugins
• userdata_pub/plugins/{vendor}/{plugintype}/{pluginname}/wtf-plugin.php
• userdata_pub/{tenantdir}/{vendor}/{plugintype}/{pluginname}/wtf-plugin.php

If IO4 is installed, it uses its invoker method, otherwise a simple call_user_func, however for plugins this final callable/closure is optional to use or not.