Refactor endpoint services to accept narrow inputs

Endpoints/SuggestionInput.cs

@@ -0,0 +1,12 @@
+namespace GameList.Endpoints;
+
+internal readonly record struct SuggestionInput(
+    string Name,
+    string? Genre,
+    string? Description,
+    string? ScreenshotUrl,
+    string? YoutubeUrl,
+    string? GameUrl,
+    int? MinPlayers,
+    int? MaxPlayers
+);