Onclick attribute for links

Added the ability to specify the onclick attribute. It can be used to specify the goals of analytics systems or for your own js code.

Wrapped Editor

The editor field for additional text took up most of the screen, which was inconvenient when working with a large number of elements. The editor field is now hidden behind Bootstrap Accordion. Fix #7

Joomla 5 dark theme support

Fixed cases of incorrect display when using a dark theme in Joomla 5.

Code refactoring

A small cleaning of the code has been carried out.