Hi,

A small feature request for db<>fiddle.

Running this query on [db<>fiddle](https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=1af1fc4e0a1b5ce267fe2d9d82595ace) returns NULL:

    SELECT CONVERT_TZ(NOW(), 'Europe/Dublin', 'America/Los_Angeles') AS conv;

Result:

    conv
    NULL
    
   
The null here is (probably) caused by not loading the [IANA](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List) time zones as outlined [here](https://dev.mysql.com/doc/refman/8.0/en/time-zone-support.html#time-zone-installation).


    
Compared with [db-fiddle.com](https://www.db-fiddle.com/f/dGLPHQFjAP17pUe1rGYyjn/0) 

Result:

    conv
    2022-01-03 03:49:44
    
or [sqlize.online](https://sqlize.online/sql/mysql57/a8bf60048ab0dadaf8ffa7a562cae2ce/)

Result:


```
+=====================+
| conv                |
+=====================+
| 2022-01-03 03:51:58 |
+---------------------+
```

This is potentially useful functionality for anyone who has to deal with timezones - db<>fiddle offers an OFFSET functionality (see last snippet in fiddle above) but this does not take into account DST (Daylight Savings Time) which can be important.

Should you require any further details or clarification and/or input, please don't hesitate to let me know.