2023-08-25 ECA Sprint: Working with dates and time

[Working with dates and time](https://ecaguide.org/library/simple/working-with-dates-and-time/) This model works with a date and time value from a node field and does various things to it: outputting in different formats, adding some time range, changing timezone, etc. Especially the timezone feature requires a [patch to the tamper module](https://www.drupal.org/project/tamper/issues/3268276#comment-15000895).