Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/tkinter/filedialog.pyi

@@ -0,0 +1,67 @@
+from tkinter import Button, Entry, Frame, Listbox, Scrollbar, Toplevel, commondialog
+from typing import Any, ClassVar, Dict, Optional, Tuple
+
+dialogstates: Dict[Any, Tuple[Any, Any]]
+
+class FileDialog:
+    title: str = ...
+    master: Any = ...
+    directory: Optional[Any] = ...
+    top: Toplevel = ...
+    botframe: Frame = ...
+    selection: Entry = ...
+    filter: Entry = ...
+    midframe: Entry = ...
+    filesbar: Scrollbar = ...
+    files: Listbox = ...
+    dirsbar: Scrollbar = ...
+    dirs: Listbox = ...
+    ok_button: Button = ...
+    filter_button: Button = ...
+    cancel_button: Button = ...
+    def __init__(
+        self, master, title: Optional[Any] = ...
+    ) -> None: ...  # title is usually a str or None, but e.g. int doesn't raise en exception either
+    how: Optional[Any] = ...
+    def go(self, dir_or_file: Any = ..., pattern: str = ..., default: str = ..., key: Optional[Any] = ...): ...
+    def quit(self, how: Optional[Any] = ...) -> None: ...
+    def dirs_double_event(self, event) -> None: ...
+    def dirs_select_event(self, event) -> None: ...
+    def files_double_event(self, event) -> None: ...
+    def files_select_event(self, event) -> None: ...
+    def ok_event(self, event) -> None: ...
+    def ok_command(self) -> None: ...
+    def filter_command(self, event: Optional[Any] = ...) -> None: ...
+    def get_filter(self): ...
+    def get_selection(self): ...
+    def cancel_command(self, event: Optional[Any] = ...) -> None: ...
+    def set_filter(self, dir, pat) -> None: ...
+    def set_selection(self, file) -> None: ...
+
+class LoadFileDialog(FileDialog):
+    title: str = ...
+    def ok_command(self) -> None: ...
+
+class SaveFileDialog(FileDialog):
+    title: str = ...
+    def ok_command(self): ...
+
+class _Dialog(commondialog.Dialog): ...
+
+class Open(_Dialog):
+    command: ClassVar[str] = ...
+
+class SaveAs(_Dialog):
+    command: ClassVar[str] = ...
+
+class Directory(commondialog.Dialog):
+    command: ClassVar[str] = ...
+
+def askopenfilename(**options): ...
+def asksaveasfilename(**options): ...
+def askopenfilenames(**options): ...
+def askopenfile(mode: str = ..., **options): ...
+def askopenfiles(mode: str = ..., **options): ...
+def asksaveasfile(mode: str = ..., **options): ...
+def askdirectory(**options): ...
+def test() -> None: ...