Remove cudf._lib.timezone in favor of inlining pylibcudf (#17366)

Contributes to #17317

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)

Approvers:
  - James Lamb (https://github.com/jameslamb)
  - Bradley Dice (https://github.com/bdice)

URL: #17366

python/cudf/cudf/_lib/CMakeLists.txt

@@ -41,7 +41,6 @@ set(cython_sources
     string_casting.pyx
     strings_udf.pyx
     text.pyx
-    timezone.pyx
     transform.pyx
     types.pyx
     utils.pyx

python/cudf/cudf/_lib/__init__.py

@@ -28,7 +28,6 @@
     strings,
     strings_udf,
     text,
-    timezone,
 )
 
 MAX_COLUMN_SIZE = np.iinfo(np.int32).max

python/cudf/cudf/core/_internals/timezones.py

@@ -10,8 +10,10 @@
 import numpy as np
 import pandas as pd
 
+import pylibcudf as plc
+
 import cudf
-from cudf._lib.timezone import make_timezone_transition_table
+from cudf._lib.column import Column
 
 if TYPE_CHECKING:
     from cudf.core.column.datetime import DatetimeColumn
@@ -109,11 +111,14 @@ def _find_and_read_tzfile_tzdata(
 
 
 def _read_tzfile_as_columns(
-    tzdir, zone_name: str
+    tzdir: str, zone_name: str
 ) -> tuple[DatetimeColumn, TimeDeltaColumn]:
-    transition_times_and_offsets = make_timezone_transition_table(
+    plc_table = plc.io.timezone.make_timezone_transition_table(
         tzdir, zone_name
     )
+    transition_times_and_offsets = [
+        Column.from_pylibcudf(col) for col in plc_table.columns()
+    ]
 
     if not transition_times_and_offsets:
         from cudf.core.column.column import as_column