GX-Entwicklung

The list of selectable time zones in the new configurations pages only lists a few options. After talking with Wilken and Till, we decided, that this selection should be improved like:

1. Add additional entries for all missing time zones.
2. Group multiple entries for the same time zone, like:
   • (GMT -1:00) Azores, Cape Verde Islands
   • (GMT) Western Europe Time, London, Lisbon, Casablanca
   • (GMT +1:00) Brussels, Copenhagen, Madrid, Paris
3. A prefix with the GMT time should be added for each entry. (See examples above.)

It's important to mention, that the selected value will be processed by PHP and incorrect values will cause errors. It's also important to know, that these values may be different from server to server, that's why it's important to use the DateTimeZone::listAbbreviations() method (see https://www.php.net/manual/de/datetimezone.listabbreviations.php for more details).