Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/imp.pyi

@@ -0,0 +1,64 @@
+import os
+import types
+from _typeshed import StrPath
+from typing import IO, Any, List, Optional, Protocol, Tuple, TypeVar, Union
+
+from _imp import (
+    acquire_lock as acquire_lock,
+    create_dynamic as create_dynamic,
+    get_frozen_object as get_frozen_object,
+    init_frozen as init_frozen,
+    is_builtin as is_builtin,
+    is_frozen as is_frozen,
+    is_frozen_package as is_frozen_package,
+    lock_held as lock_held,
+    release_lock as release_lock,
+)
+
+_T = TypeVar("_T")
+
+SEARCH_ERROR: int
+PY_SOURCE: int
+PY_COMPILED: int
+C_EXTENSION: int
+PY_RESOURCE: int
+PKG_DIRECTORY: int
+C_BUILTIN: int
+PY_FROZEN: int
+PY_CODERESOURCE: int
+IMP_HOOK: int
+
+def new_module(name: str) -> types.ModuleType: ...
+def get_magic() -> bytes: ...
+def get_tag() -> str: ...
+def cache_from_source(path: StrPath, debug_override: Optional[bool] = ...) -> str: ...
+def source_from_cache(path: StrPath) -> str: ...
+def get_suffixes() -> List[Tuple[str, str, int]]: ...
+
+class NullImporter:
+    def __init__(self, path: StrPath) -> None: ...
+    def find_module(self, fullname: Any) -> None: ...
+
+# Technically, a text file has to support a slightly different set of operations than a binary file,
+# but we ignore that here.
+class _FileLike(Protocol):
+    closed: bool
+    mode: str
+    def read(self) -> Union[str, bytes]: ...
+    def close(self) -> Any: ...
+    def __enter__(self) -> Any: ...
+    def __exit__(self, *args: Any) -> Any: ...
+
+# PathLike doesn't work for the pathname argument here
+def load_source(name: str, pathname: str, file: Optional[_FileLike] = ...) -> types.ModuleType: ...
+def load_compiled(name: str, pathname: str, file: Optional[_FileLike] = ...) -> types.ModuleType: ...
+def load_package(name: str, path: StrPath) -> types.ModuleType: ...
+def load_module(name: str, file: Optional[_FileLike], filename: str, details: Tuple[str, str, int]) -> types.ModuleType: ...
+
+# IO[Any] is a TextIOWrapper if name is a .py file, and a FileIO otherwise.
+def find_module(
+    name: str, path: Union[None, List[str], List[os.PathLike[str]], List[StrPath]] = ...
+) -> Tuple[IO[Any], str, Tuple[str, str, int]]: ...
+def reload(module: types.ModuleType) -> types.ModuleType: ...
+def init_builtin(name: str) -> Optional[types.ModuleType]: ...
+def load_dynamic(name: str, path: str, file: Any = ...) -> types.ModuleType: ...  # file argument is ignored