Re-export and deprecate typing and bit_masks modules

src/pystencils/bit_masks.py

+from .sympyextensions.bit_masks import flag_cond as _flag_cond
+
+from warnings import warn
+warn(
+    "Importing the `pystencils.bit_masks` module is deprecated. "
+    "Import `flag_cond` from `pystencils.sympyextensions` instead."
+)
+
+flag_cond = _flag_cond

src/pystencils/typing.py

+from .sympyextensions import TypedSymbol as _TypedSymbol
+from .types import create_type as _create_type
+
+from warnings import warn
+warn(
+    "Importing `TypedSymbol` and `create_type` from `pystencils.typing` is deprecated. "
+    "Import from `pystencils` instead."
+)
+
+TypedSymbol = _TypedSymbol
+create_type = _create_type