Stardew Valley: Move BaseTest out of __init__.py to comply with future conventions (#4991)

* move everything out of init; fix from imports and some typing errors

* why is there a change in multiserver

* fix some relative shits

worlds/stardew_valley/test/TestFriendsanity.py

@@ -2,7 +2,7 @@ import unittest
 from collections import Counter
 from typing import ClassVar, Set
 
-from . import SVTestBase
+from .bases import SVTestBase
 from ..content.feature import friendsanity
 from ..options import Friendsanity, FriendsanityHeartSize