IPC - Refactor Bcat service to use new ipc - Revisit (#4803)

* bcat ipc

* fix hipc buffer flags

* add buffer fixed size flag on generator

src/Ryujinx.Horizon/Sdk/Bcat/IDeliveryCacheDirectoryService.cs

@@ -0,0 +1,14 @@
+using LibHac.Bcat;
+using Ryujinx.Horizon.Common;
+using Ryujinx.Horizon.Sdk.Sf;
+using System;
+
+namespace Ryujinx.Horizon.Sdk.Bcat
+{
+    internal interface IDeliveryCacheDirectoryService : IServiceObject
+    {
+        Result GetCount(out int count);
+        Result Open(DirectoryName directoryName);
+        Result Read(out int entriesRead, Span<DeliveryCacheDirectoryEntry> entriesBuffer);
+    }
+}