Fix regression with downloader mapper on aria2c and saldl

The setup I had for using asyncio.run with functools.partial didn't actually pan out. A full pass-through lambda is required.

I've also moved the mapped downloader variable to the root of the downloaders package.

devine/core/downloaders/__init__.py

@@ -1,6 +1,15 @@
+import asyncio
+
 from .aria2c import aria2c
 from .requests import requests
 from .saldl import saldl
-from .downloader import downloader
+from ..config import config
+
+downloader = {
+    "aria2c": lambda *args, **kwargs: asyncio.run(aria2c(*args, **kwargs)),
+    "requests": requests,
+    "saldl": lambda *args, **kwargs: asyncio.run(saldl(*args, **kwargs))
+}[config.downloader]
+
 
 __ALL__ = (downloader, aria2c, requests, saldl)

devine/core/downloaders/downloader.py

@@ -1,12 +0,0 @@
-import asyncio
-from functools import partial
-
-from devine.core.config import config
-from devine.core.downloaders import aria2c, requests, saldl
-
-
-downloader = {
-    "aria2c": partial(asyncio.run, aria2c),
-    "requests": requests,
-    "saldl": partial(asyncio.run, saldl)
-}[config.downloader]