allow ARROW_CAST to cast to TimestampTz

[waitingkuo]

Is your feature request related to a problem or challenge?

ARROW_CAST was added in #5166 by @alamb which enable casting to arbitrary arrotypes.

However, casting to timetamptz (e.g. Timestamp(Nanosecond, Some("+00:00")) isn't supported yet

Describe the solution you'd like

make this work

❯ select arrow_cast(now(), 'Timestamp(Nanosecond, Some( "+08:00" ))');
+----------------------------------+
| now()                            |
+----------------------------------+
| 2023-04-07T19:42:22.197975+08:00 |
+----------------------------------+
1 row in set. Query took 0.002 seconds.

Describe alternatives you've considered

No response

Additional context

No response