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GH-39702: [GLib] Add support for time zone in GArrowTimestampDataType (#39717)

### Rationale for this change

Timestamp data type in Apache Arrow supports time zone but Apache Arrow C GLib didn't support it. Timestamp data type has "timezone-aware" mode and "timezone-naive" mode. If a timestamp data type has a valid time zone information, it uses "timezone-aware" mode. If a timestamp data type doesn't have a valid time zone information, it uses "timezone-naive" mode. Apache Arrow C GLib should support both of them.

### What changes are included in this PR?

This change adds a new `GTimeZone *time_zone` argument to `garrow_timestamp_data_type_new()` instead of adding a new `garrow_timestamp_data_type_new_time_zone()` function. This breaks backward compatibility for Apache Arrow C GLib users. But this still keeps backward compatibility for users of bindings such as Ruby and Vala. Because the new `GTimeZone *time_zone` is nullable.

I tried to use the "adding a new
`garrow_timestamp_data_type_new_time_zone()` function" approach but Vala didn't like it. Both of
`garrow_timestamp_data_type_new_time_zone()` (constructor) and `garrow_timestamp_data_type_get_time_zone()` (instance method or property reader) were mapped to
`GArrow.TimestampDataType.time_zone()`.

So I chose the "adding a new argument to
`garrow_timestamp_data_type_new()`" approach.

### Are these changes tested?

Yes.

### Are there any user-facing changes?

Yes.

**This PR includes breaking changes to public APIs.**

* Closes: #39702

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>