Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stubs/DateTimeRange/datetimerange/__init__.pyi

@@ -0,0 +1,47 @@
+import datetime
+from typing import Iterable, Optional, Union
+
+from dateutil.relativedelta import relativedelta
+
+class DateTimeRange(object):
+    NOT_A_TIME_STR: str
+    start_time_format: str
+    end_time_format: str
+    is_output_elapse: bool
+    separator: str
+    def __init__(
+        self,
+        start_datetime: Optional[Union[datetime.datetime, str]] = ...,
+        end_datetime: Optional[Union[datetime.datetime, str]] = ...,
+        start_time_format: str = ...,
+        end_time_format: str = ...,
+    ) -> None: ...
+    def __eq__(self, other) -> bool: ...
+    def __ne__(self, other) -> bool: ...
+    def __add__(self, other) -> DateTimeRange: ...
+    def __iadd__(self, other) -> DateTimeRange: ...
+    def __sub__(self, other) -> DateTimeRange: ...
+    def __isub__(self, other) -> DateTimeRange: ...
+    def __contains__(self, x) -> bool: ...
+    @property
+    def start_datetime(self) -> datetime.datetime: ...
+    @property
+    def end_datetime(self) -> datetime.datetime: ...
+    @property
+    def timedelta(self) -> datetime.timedelta: ...
+    def is_set(self) -> bool: ...
+    def validate_time_inversion(self) -> None: ...
+    def is_valid_timerange(self) -> bool: ...
+    def is_intersection(self, x) -> bool: ...
+    def get_start_time_str(self) -> str: ...
+    def get_end_time_str(self) -> str: ...
+    def get_timedelta_second(self) -> float: ...
+    def set_start_datetime(self, value: Optional[Union[datetime.datetime, str]], timezone: Optional[str] = ...) -> None: ...
+    def set_end_datetime(self, value: Optional[Union[datetime.datetime, str]], timezone: Optional[str] = ...) -> None: ...
+    def set_time_range(
+        self, start: Optional[Union[datetime.datetime, str]], end: Optional[Union[datetime.datetime, str]]
+    ) -> None: ...
+    def range(self, step: Union[datetime.timedelta, relativedelta]) -> Iterable[datetime.datetime]: ...
+    def intersection(self, x: DateTimeRange) -> DateTimeRange: ...
+    def encompass(self, x: DateTimeRange) -> DateTimeRange: ...
+    def truncate(self, percentage: float) -> None: ...