feat: add required attribute to cron.xml

In this commit, we have improved the handling of cron tasks and introduced the 'required' attribute. Changes made include:

• Added 'required' attribute to three cron exec in cron.xml to enforce their creation.
• Updated EventHandler to only create required crons, and to stop creating non-required crons when the $onlyRequired argument is set to true.
• Improved how crons are created with different scopes by replacing the switch statement with a match expression in EventHandler.
• Added the handling of the 'required' attribute in Manager to ensure all cron objects are aware of if they are required or not. This attribute is set to true for required crons and false if not specified or not required.
• Simplified the array replacement in EventHandler.

This improvement in how cron tasks are managed will result in more efficient and robust operation of the system.