Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/@python2/rfc822.pyi

@@ -0,0 +1,75 @@
+from typing import Any, Optional
+
+class Message:
+    fp: Any
+    seekable: Any
+    startofheaders: Any
+    startofbody: Any
+    def __init__(self, fp, seekable: int = ...): ...
+    def rewindbody(self): ...
+    dict: Any
+    unixfrom: Any
+    headers: Any
+    status: Any
+    def readheaders(self): ...
+    def isheader(self, line): ...
+    def islast(self, line): ...
+    def iscomment(self, line): ...
+    def getallmatchingheaders(self, name): ...
+    def getfirstmatchingheader(self, name): ...
+    def getrawheader(self, name): ...
+    def getheader(self, name, default: Optional[Any] = ...): ...
+    get: Any
+    def getheaders(self, name): ...
+    def getaddr(self, name): ...
+    def getaddrlist(self, name): ...
+    def getdate(self, name): ...
+    def getdate_tz(self, name): ...
+    def __len__(self): ...
+    def __getitem__(self, name): ...
+    def __setitem__(self, name, value): ...
+    def __delitem__(self, name): ...
+    def setdefault(self, name, default=...): ...
+    def has_key(self, name): ...
+    def __contains__(self, name): ...
+    def __iter__(self): ...
+    def keys(self): ...
+    def values(self): ...
+    def items(self): ...
+
+class AddrlistClass:
+    specials: Any
+    pos: Any
+    LWS: Any
+    CR: Any
+    atomends: Any
+    phraseends: Any
+    field: Any
+    commentlist: Any
+    def __init__(self, field): ...
+    def gotonext(self): ...
+    def getaddrlist(self): ...
+    def getaddress(self): ...
+    def getrouteaddr(self): ...
+    def getaddrspec(self): ...
+    def getdomain(self): ...
+    def getdelimited(self, beginchar, endchars, allowcomments: int = ...): ...
+    def getquote(self): ...
+    def getcomment(self): ...
+    def getdomainliteral(self): ...
+    def getatom(self, atomends: Optional[Any] = ...): ...
+    def getphraselist(self): ...
+
+class AddressList(AddrlistClass):
+    addresslist: Any
+    def __init__(self, field): ...
+    def __len__(self): ...
+    def __add__(self, other): ...
+    def __iadd__(self, other): ...
+    def __sub__(self, other): ...
+    def __isub__(self, other): ...
+    def __getitem__(self, index): ...
+
+def parsedate_tz(data): ...
+def parsedate(data): ...
+def mktime_tz(data): ...