Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/faulthandler.pyi

@@ -0,0 +1,13 @@
+import sys
+from _typeshed import FileDescriptorLike
+
+def cancel_dump_traceback_later() -> None: ...
+def disable() -> None: ...
+def dump_traceback(file: FileDescriptorLike = ..., all_threads: bool = ...) -> None: ...
+def dump_traceback_later(timeout: float, repeat: bool = ..., file: FileDescriptorLike = ..., exit: bool = ...) -> None: ...
+def enable(file: FileDescriptorLike = ..., all_threads: bool = ...) -> None: ...
+def is_enabled() -> bool: ...
+
+if sys.platform != "win32":
+    def register(signum: int, file: FileDescriptorLike = ..., all_threads: bool = ..., chain: bool = ...) -> None: ...
+    def unregister(signum: int) -> None: ...