Base for 4.3 work. Split Nadeko.Common into a separate project

src/NadekoBot/Modules/Games/Trivia/DefaultQuestionPool.cs

@@ -0,0 +1,33 @@
+namespace NadekoBot.Modules.Games.Common.Trivia;
+
+public sealed class DefaultQuestionPool : IQuestionPool
+{
+    private readonly ILocalDataCache _cache;
+    private readonly NadekoRandom _rng;
+
+    public DefaultQuestionPool(ILocalDataCache cache)
+    {
+        _cache = cache;
+        _rng = new NadekoRandom();
+    }
+    public async Task<TriviaQuestion?> GetRandomQuestionAsync(ISet<TriviaQuestion> exclude)
+    {
+        TriviaQuestion randomQuestion;
+        var pool = await _cache.GetTriviaQuestionsAsync();
+        
+        if(pool is null)
+            return default;
+        
+        while (exclude.Contains(randomQuestion = new(pool[_rng.Next(0, pool.Length)])))
+        {
+            // if too many questions are excluded, clear the exclusion list and start over
+            if (exclude.Count > pool.Length / 10 * 9)
+            {
+                exclude.Clear();
+                break;
+            }
+        }
+
+        return randomQuestion;
+    }
+}