Add database settings binding and conditional Redis cache

Bind database settings from configuration and conditionally register Redis cache service based on the presence of Redis settings.

Author: Oceania2018

src/Infrastructure/BotSharp.Core/BotSharpCoreExtensions.cs

@@ -49,7 +49,15 @@ private static void AddCacheServices(IServiceCollection services, IConfiguration
         config.Bind("SharpCache", cacheSettings);
         services.AddSingleton(x => cacheSettings);
 
-        services.AddSingleton<RedisCacheService>();
+        var dbSettings = new BotSharpDatabaseSettings();
+        config.Bind("Database", dbSettings);
+
+        if (!string.IsNullOrEmpty(dbSettings.Redis))
+        {
+            services.AddSingleton<RedisCacheService>();
+            return;
+        }
+        
         services.AddSingleton<ICacheService>(sp => cacheSettings.CacheType switch
         {
             CacheType.RedisCache => ActivatorUtilities.CreateInstance<RedisCacheService>(sp),