Re-organize directory structure (#4971)

See discussion in #2491

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

stubs/pymssql/METADATA.toml

@@ -0,0 +1,3 @@
+version = "0.1"
+python2 = true
+python3 = false

stubs/pymssql/pymssql.pyi

@@ -0,0 +1,44 @@
+from datetime import date, datetime, time
+from typing import Any, Dict, Iterable, List, Optional, Sequence, Tuple, Union
+
+Scalar = Union[int, float, str, datetime, date, time]
+Result = Union[Tuple[Scalar, ...], Dict[str, Scalar]]
+
+class Connection(object):
+    def __init__(self, user, password, host, database, timeout, login_timeout, charset, as_dict) -> None: ...
+    def autocommit(self, status: bool) -> None: ...
+    def close(self) -> None: ...
+    def commit(self) -> None: ...
+    def cursor(self) -> Cursor: ...
+    def rollback(self) -> None: ...
+
+class Cursor(object):
+    def __init__(self) -> None: ...
+    def __iter__(self): ...
+    def __next__(self) -> Any: ...
+    def callproc(self, procname: str, **kwargs) -> None: ...
+    def close(self) -> None: ...
+    def execute(self, stmt: str, params: Optional[Union[Scalar, Tuple[Scalar, ...], Dict[str, Scalar]]]) -> None: ...
+    def executemany(self, stmt: str, params: Optional[Sequence[Tuple[Scalar, ...]]]) -> None: ...
+    def fetchall(self) -> List[Result]: ...
+    def fetchmany(self, size: Optional[int]) -> List[Result]: ...
+    def fetchone(self) -> Result: ...
+
+def connect(
+    server: Optional[str],
+    user: Optional[str],
+    password: Optional[str],
+    database: Optional[str],
+    timeout: Optional[int],
+    login_timeout: Optional[int],
+    charset: Optional[str],
+    as_dict: Optional[bool],
+    host: Optional[str],
+    appname: Optional[str],
+    port: Optional[str],
+    conn_properties: Optional[Union[str, Sequence[str]]],
+    autocommit: Optional[bool],
+    tds_version: Optional[str],
+) -> Connection: ...
+def get_max_connections() -> int: ...
+def set_max_connections(n: int) -> None: ...