Rename online store class to better explain what it's doing

Author: peppy

osu.Game/Audio/PreviewTrackManager.cs

@@ -30,7 +30,7 @@ public PreviewTrackManager(IAdjustableAudioComponent mainTrackAdjustments)
         [BackgroundDependencyLoader]
         private void load(AudioManager audioManager)
         {
-            trackStore = audioManager.GetTrackStore(new OsuOnlineStore());
+            trackStore = audioManager.GetTrackStore(new TrustedDomainOnlineStore());
         }
 
         /// <summary>

osu.Game/Online/OsuOnlineStore.cs osu.Game/Online/TrustedDomainOnlineStore.cs

@@ -7,7 +7,7 @@
 
 namespace osu.Game.Online
 {
-    public class OsuOnlineStore : OnlineStore
+    public sealed class TrustedDomainOnlineStore : OnlineStore
     {
         protected override string GetLookupUrl(string url)
         {

osu.Game/OsuGameBase.cs

@@ -108,7 +108,7 @@ public partial class OsuGameBase : Framework.Game, ICanAcceptFiles, IBeatSyncPro
         public virtual EndpointConfiguration CreateEndpoints() =>
             UseDevelopmentServer ? new DevelopmentEndpointConfiguration() : new ProductionEndpointConfiguration();
 
-        protected override OnlineStore CreateOnlineStore() => new OsuOnlineStore();
+        protected override OnlineStore CreateOnlineStore() => new TrustedDomainOnlineStore();
 
         public virtual Version AssemblyVersion => Assembly.GetEntryAssembly()?.GetName().Version ?? new Version();