TYPING: add skeleton stub for Timestamp
xref #28133

This PR adds just the skeleton so that the attributes, methods and arguments available are known.

in this PR, the methods starting with an underscore have been omitted and the attributes typed with Any. This follows default stubgen output. https://mypy.readthedocs.io/en/latest/stubgen.html#automatic-stub-generation-stubgen

fix for `pandas\core\arrays\datetimes.py:275: error: Incompatible types in assignment (expression has type "Type[Timestamp]", base class "AttributesMixin" defined the type as "Type[DatetimeLikeScalar]")` arising from adding type information for Timestamp.

relevant diff for `mypy pandas --disallow-any-unimported`...

```
< pandas\_typing.py:23: error: Constraint 2 becomes "Any" due to an unfollowed import
7d5
< pandas\core\dtypes\dtypes.py:653: error: Type of variable becomes "Type[Any]" due to an unfollowed import
44,45d41
< pandas\core\arrays\_ranges.py:15: error: Argument 1 to "generate_regular_range" becomes "Any" due to an unfollowed import
< pandas\core\arrays\_ranges.py:15: error: Argument 2 to "generate_regular_range" becomes "Any" due to an unfollowed import
129c125
< pandas\io\formats\format.py:1550: error: Argument 1 to "_format_datetime64" becomes "Union[Any, Any]" due to an unfollowed import
---
> pandas\io\formats\format.py:1550: error: Argument 1 to "_format_datetime64" becomes "Union[Any, Timestamp]" due to an unfollowed import
131c127
< pandas\io\formats\format.py:1567: error: Argument 1 to "_format_datetime64_dateonly" becomes "Union[Any, Any]" due to an unfollowed import
---
> pandas\io\formats\format.py:1567: error: Argument 1 to "_format_datetime64_dateonly" becomes "Union[Any, Timestamp]" due to an unfollowed import
```