Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/@python2/commands.pyi

@@ -0,0 +1,10 @@
+from typing import AnyStr, Text, Tuple, overload
+
+def getstatus(file: Text) -> str: ...
+def getoutput(cmd: Text) -> str: ...
+def getstatusoutput(cmd: Text) -> Tuple[int, str]: ...
+@overload
+def mk2arg(head: bytes, x: bytes) -> bytes: ...
+@overload
+def mk2arg(head: Text, x: Text) -> Text: ...
+def mkarg(x: AnyStr) -> AnyStr: ...