Adds user settings for the Castle extension

Adds functionality to configure the Castle extension, including a wallet ID.

This allows administrators to customize the extension's behavior by specifying a dedicated wallet for castle operations.

services.py

@@ -0,0 +1,23 @@
+from .crud import (
+    create_castle_settings,
+    get_castle_settings,
+    update_castle_settings,
+)
+from .models import CastleSettings
+
+
+async def get_settings(user_id: str) -> CastleSettings:
+    settings = await get_castle_settings(user_id)
+    if not settings:
+        settings = await create_castle_settings(user_id, CastleSettings())
+    return settings
+
+
+async def update_settings(user_id: str, data: CastleSettings) -> CastleSettings:
+    settings = await get_castle_settings(user_id)
+    if not settings:
+        settings = await create_castle_settings(user_id, data)
+    else:
+        settings = await update_castle_settings(user_id, data)
+
+    return settings