Core: Add settings API ("auto settings") for host.yaml (#1871)

* Add settings API ("auto settings") for host.yaml

* settings: no BOM when saving

* settings: fix saving / groups resetting themselves

* settings: fix AutoWorldRegister import

Co-authored-by: el-u <109771707+el-u@users.noreply.github.com>

* Lufia2: settings: clean up imports

* settings: more consistent class naming

* Docs: update world api for settings api refactor

* settings: fix access from World instance

* settings: update migration timeline

* Docs: Apply suggestions from code review

Co-authored-by: Zach Parks <zach@alliware.com>

* Settings: correctly resolve .exe in UserPath and LocalPath

---------

Co-authored-by: el-u <109771707+el-u@users.noreply.github.com>
Co-authored-by: Zach Parks <zach@alliware.com>

worlds/smw/__init__.py

@@ -1,6 +1,7 @@
 import os
 import typing
 import math
+import settings
 import threading
 
 from BaseClasses import Item, MultiWorld, Tutorial, ItemClassification
@@ -17,6 +18,16 @@ from worlds.AutoWorld import WebWorld, World
 from .Rom import LocalRom, patch_rom, get_base_rom_path, SMWDeltaPatch
 
 
+class SMWSettings(settings.Group):
+    class RomFile(settings.SNESRomPath):
+        """File name of the SMW US rom"""
+        description = "Super Mario World (USA) ROM File"
+        copy_to = "Super Mario World (USA).sfc"
+        md5s = [SMWDeltaPatch.hash]
+
+    rom_file: RomFile = RomFile(RomFile.copy_to)
+
+
 class SMWWeb(WebWorld):
     theme = "grass"
 
@@ -40,6 +51,7 @@ class SMWWorld(World):
     """
     game: str = "Super Mario World"
     option_definitions = smw_options
+    settings: typing.ClassVar[SMWSettings]
     topology_present = False
     data_version = 3
     required_client_version = (0, 3, 5)