Make it an importable module

Abandon DuckDB in favor of sqlite3

src/gptbot/commands/ignoreolder.py

@@ -0,0 +1,9 @@
+from nio.events.room_events import RoomMessageText
+from nio.rooms import MatrixRoom
+
+async def command_ignoreolder(room: MatrixRoom, event: RoomMessageText, bot):
+    body = """Alright, messages before this point will not be processed as context anymore.
+                                         
+If you ever reconsider, you can simply delete your message and I will start processing messages before it again."""
+
+    await bot.send_message(room, body, True)