Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/getopt.pyi

@@ -0,0 +1,10 @@
+from typing import List, Tuple
+
+def getopt(args: List[str], shortopts: str, longopts: List[str] = ...) -> Tuple[List[Tuple[str, str]], List[str]]: ...
+def gnu_getopt(args: List[str], shortopts: str, longopts: List[str] = ...) -> Tuple[List[Tuple[str, str]], List[str]]: ...
+
+class GetoptError(Exception):
+    msg: str
+    opt: str
+
+error = GetoptError