Upgrade architecture + 5.0 Bot API (#469)

Upgrade architecture + 5.0 Bot API (#469)
* Moved `methods`, `types` and `client` to root package
* Removed update handler from routers to dispatcher
* Reworked events propagation mechanism to handlers
* Reworked inner middlewares logic (very small change)
* Updated to Bot API 5.0
* Initial migration from MkDocs to Sphinx + config for readthedocs

tests/test_api/test_methods/test_copy_message.py

@@ -0,0 +1,35 @@
+import pytest
+
+from aiogram.methods import CopyMessage, Request
+from aiogram.types import MessageId
+from tests.mocked_bot import MockedBot
+
+
+class TestCopyMessage:
+    @pytest.mark.asyncio
+    async def test_method(self, bot: MockedBot):
+        prepare_result = bot.add_result_for(CopyMessage, ok=True, result=MessageId(message_id=42))
+
+        response: MessageId = await CopyMessage(
+            chat_id=42,
+            from_chat_id=42,
+            message_id=42,
+        )
+        request: Request = bot.get_request()
+        assert request.method == "copyMessage"
+        # assert request.data == {}
+        assert response == prepare_result.result
+
+    @pytest.mark.asyncio
+    async def test_bot_method(self, bot: MockedBot):
+        prepare_result = bot.add_result_for(CopyMessage, ok=True, result=MessageId(message_id=42))
+
+        response: MessageId = await bot.copy_message(
+            chat_id=42,
+            from_chat_id=42,
+            message_id=42,
+        )
+        request: Request = bot.get_request()
+        assert request.method == "copyMessage"
+        # assert request.data == {}
+        assert response == prepare_result.result