Generate settings pages automatically.

This adds metadata to settings fields that can be used to automatically
generate the settings window. For now I have replaced the Difficulty
page. Will follow up to replace the others.

game/settings/skilloption.py

@@ -0,0 +1,20 @@
+from typing import Any, Optional
+
+from .choicesoption import choices_option
+
+
+def skill_option(
+    text: str,
+    page: str,
+    section: str,
+    detail: Optional[str] = None,
+    **kwargs: Any,
+) -> str:
+    return choices_option(
+        text,
+        page,
+        section,
+        ["Average", "Good", "High", "Excellent"],
+        detail=detail,
+        **kwargs,
+    )