[entertainment] add guess game

Core/Cache/ICacheStorage.cs

@@ -6,5 +6,6 @@ namespace Kruzya.TelegramBot.Core.Cache
     {
         public bool TryGetValue(TKey key, out TValue value);
         public void SetValue(TKey key, TValue value, int timeToLive);
+        public TValue GetOr(TKey key, TValue value);
     }
 }

Core/Cache/MemoryCache.cs

@@ -72,6 +72,17 @@ namespace Kruzya.TelegramBot.Core.Cache
             return true;
         }
 
+        public TValue GetOr(TKey key, TValue defValue = default)
+        {
+            var doesExist = TryGetValue(key, out var value);
+            if (!doesExist)
+            {
+                value = defValue;
+            }
+
+            return value;
+        }
+
         public void SetValue(TKey key, TValue value)
         {
             SetValue(key, value, _defaultTtl);