Dev 3.x flat package (#961)

* Move packages

* Added changelog

* Update examples/echo_bot.py

Co-authored-by: Oleg A. <t0rr@mail.ru>

* Rename `handler` -> `handlers`

* Update __init__.py

Co-authored-by: Oleg A. <t0rr@mail.ru>

aiogram/fsm/context.py

@@ -0,0 +1,34 @@
+from typing import Any, Dict, Optional
+
+from aiogram import Bot
+from aiogram.fsm.storage.base import BaseStorage, StateType, StorageKey
+
+
+class FSMContext:
+    def __init__(self, bot: Bot, storage: BaseStorage, key: StorageKey) -> None:
+        self.bot = bot
+        self.storage = storage
+        self.key = key
+
+    async def set_state(self, state: StateType = None) -> None:
+        await self.storage.set_state(bot=self.bot, key=self.key, state=state)
+
+    async def get_state(self) -> Optional[str]:
+        return await self.storage.get_state(bot=self.bot, key=self.key)
+
+    async def set_data(self, data: Dict[str, Any]) -> None:
+        await self.storage.set_data(bot=self.bot, key=self.key, data=data)
+
+    async def get_data(self) -> Dict[str, Any]:
+        return await self.storage.get_data(bot=self.bot, key=self.key)
+
+    async def update_data(
+        self, data: Optional[Dict[str, Any]] = None, **kwargs: Any
+    ) -> Dict[str, Any]:
+        if data:
+            kwargs.update(data)
+        return await self.storage.update_data(bot=self.bot, key=self.key, data=kwargs)
+
+    async def clear(self) -> None:
+        await self.set_state(state=None)
+        await self.set_data({})