Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/_msi.pyi

@@ -0,0 +1,49 @@
+import sys
+from typing import List, Optional, Union
+
+if sys.platform == "win32":
+
+    # Actual typename View, not exposed by the implementation
+    class _View:
+        def Execute(self, params: Optional[_Record] = ...) -> None: ...
+        def GetColumnInfo(self, kind: int) -> _Record: ...
+        def Fetch(self) -> _Record: ...
+        def Modify(self, mode: int, record: _Record) -> None: ...
+        def Close(self) -> None: ...
+        # Don't exist at runtime
+        __new__: None  # type: ignore
+        __init__: None  # type: ignore
+    # Actual typename Summary, not exposed by the implementation
+    class _Summary:
+        def GetProperty(self, propid: int) -> Optional[Union[str, bytes]]: ...
+        def GetPropertyCount(self) -> int: ...
+        def SetProperty(self, propid: int, value: Union[str, bytes]) -> None: ...
+        def Persist(self) -> None: ...
+        # Don't exist at runtime
+        __new__: None  # type: ignore
+        __init__: None  # type: ignore
+    # Actual typename Database, not exposed by the implementation
+    class _Database:
+        def OpenView(self, sql: str) -> _View: ...
+        def Commit(self) -> None: ...
+        def GetSummaryInformation(self, updateCount: int) -> _Summary: ...
+        def Close(self) -> None: ...
+        # Don't exist at runtime
+        __new__: None  # type: ignore
+        __init__: None  # type: ignore
+    # Actual typename Record, not exposed by the implementation
+    class _Record:
+        def GetFieldCount(self) -> int: ...
+        def GetInteger(self, field: int) -> int: ...
+        def GetString(self, field: int) -> str: ...
+        def SetString(self, field: int, str: str) -> None: ...
+        def SetStream(self, field: int, stream: str) -> None: ...
+        def SetInteger(self, field: int, int: int) -> None: ...
+        def ClearData(self) -> None: ...
+        # Don't exist at runtime
+        __new__: None  # type: ignore
+        __init__: None  # type: ignore
+    def UuidCreate() -> str: ...
+    def FCICreate(cabname: str, files: List[str]) -> None: ...
+    def OpenDatabase(name: str, flags: int) -> _Database: ...
+    def CreateRecord(count: int) -> _Record: ...