fix: compatible with the events calendar

[sapayth]

WPUF's event calendar post form wasn't working for version 6.x.x

new hook introduced Filter hook: wpuf_tib_event_meta Description: Opportunity to change The Event Calendar metadata just before WPUF is saving it to DB @param array $event_data The event metadata @param int $post_id The post id, in other words, The Event

Action hook: wpuf_tib_after_saving_event_meta Description: Hook fired just after WPUF saved The Event Calender metadata to the DB @param int $post_id The post id, in other words, The Event

Some test scenarios

1. Check backward compatibility for The events calender version less than 6
2. Test the hooks mentioned above. Here is an example of how to use hooks in WordPress.
3. Check without the WPUF Pro version

related PR in pro #512 fix #505