Add Python bindings for time zone data (TZiF) reader

[shwina]

Description

This PR adds bindings to the TZiF reader that was added in the libcudf API in #12805.

No tests are being added as these bindings are just for internal-use. In follow-up PRs, I will add a timezone-aware datetime type and timezone-aware operations to the public API, along with tests for those operations.

The bindings can be used as follows:

>>> transition_times, offsets = make_timezone_transition_table("/usr/share/zoneinfo", "America/New_York")
                                            
>>> transition_times
<cudf.core.column.datetime.DatetimeColumn object at 0x7f95cd6ac840>
[
  1883-11-18 17:00:00,
  1883-11-18 17:00:00,
  1918-03-31 07:00:00,
  1918-10-27 06:00:00,
  1919-03-30 07:00:00,
  1919-10-26 06:00:00,
  1920-03-28 07:00:00,
  1920-10-31 06:00:00,
  1921-04-24 07:00:00,
  1921-09-25 06:00:00,
  ...
  2365-03-14 07:00:00,
  2365-11-07 06:00:00,
  2366-03-13 07:00:00,
  2366-11-06 06:00:00,
  2367-03-12 07:00:00,
  2367-11-05 06:00:00,
  2368-03-10 07:00:00,
  2368-11-03 06:00:00,
  2369-03-09 07:00:00,
  2369-11-02 06:00:00
]
dtype: datetime64[s]

>>> offsets
<cudf.core.column.timedelta.TimeDeltaColumn object at 0x7f94e69bad40>
[
  -18000,
  -18000,
  -14400,
  -18000,
  -14400,
  -18000,
  -14400,
  -18000,
  -14400,
  -18000,
  ...
  -14400,
  -18000,
  -14400,
  -18000,
  -14400,
  -18000,
  -14400,
  -18000,
  -14400,
  -18000
]
dtype: timedelta64[s]

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[bdice]

Needs a rebase because the commit history is broken but otherwise LGTM.

[shwina]

/merge