Add option to select whether to delete the already expired tokens in each cron run

I have created the form element and added the property to the settings.yml file.

Thanks! @sidharth_soman your solution does not comply with the proposed solution:

1. You added the option in the 'advanced' fielset
2. Didn't include the check on the cron hook

@Yuvania yours is almost good to go! In the cron hook, you left the token manager var definition where it shouldn't be

Thanks! This works.

Automatically closed - issue fixed for 2 weeks with no activity.