Stardew Valley: Refactor skill progression to use new feature system (#3662)

* create a first draft of the feature

* use feature in items and locations

* add content to more places

* use feature in logic

* replace option check by feature

* remove unused code

* remove weird white space

* some import nitpicking

* flip negative if

worlds/stardew_valley/test/content/__init__.py

@@ -7,7 +7,8 @@ default_features = StardewFeatures(
     feature.booksanity.BooksanityDisabled(),
     feature.cropsanity.CropsanityDisabled(),
     feature.fishsanity.FishsanityNone(),
-    feature.friendsanity.FriendsanityNone()
+    feature.friendsanity.FriendsanityNone(),
+    feature.skill_progression.SkillProgressionVanilla(),
 )