Add to_local_time function for converting timestamps with timezones to timestmaps without timezones

[alamb]

Is your feature request related to a problem or challenge?

The actual need is implementing date_bin that correctly bins dates on timezone correct timestamps (e.g. not UTC) as described by @Abdullahsab3 in #10368

This ticket tracks adding the to_local_time function portion of @Abdullahsab3 's suggestion in DataFusion while we work on getting consensus if we want to change the semantics of the arrow cast kernel: apache/arrow-rs#5826

Describe the solution you'd like

Add function to_local_time that takes a timestamp/column as an argument, and a timezone as another argument. For example

> select to_local_time('2020-11-30T08:00:00.000Z'::timestamp, 'Europe/Brussels');
-- translates to '2020-11-30T08:00:00.000Z'::timestamp + interval '1 hour'
< '2020-11-30T09:00:00'

The difference between this and the at time zone operator is:
The at time zone operator seems to be only adding timezone/offset information to the timestamp if I understood correctly. the proposed to_local_time function should ideally apply that offset to the provided timestamp. The same example above would be:

> select '2020-11-30T08:00:00.000Z'::timestamp at time zone 'Europe/Brussels';
+----------------------------------+
| Utf8("2020-11-30T08:00:00.000Z") |
+----------------------------------+
| 2020-11-30T08:00:00+01:00        |
+----------------------------------+
1 row in set. Query took 0.002 seconds.

Describe alternatives you've considered

No response

Additional context

No response