Horizon: Implement arp:r and arp:w services (#5802)

* Horizon: Implement arp:r and arp:w services

* Fix formatting

* Remove HLE arp services

* Revert "Remove HLE arp services"

This reverts commit c576fcccadb963db56b96bacabd1c1ac7abfb1ab.

* Keep LibHac impl since it's used in bcat

* Addresses gdkchan's feedback

* ArpApi in PrepoIpcServer and remove LmApi

* Fix 2

* Fixes ArpApi init

* Fix encoding

* Update PrepoService.cs

* Fix prepo

src/Ryujinx.Horizon/Arp/ArpIpcServer.cs

@@ -0,0 +1,61 @@
+using Ryujinx.Horizon.Arp.Ipc;
+using Ryujinx.Horizon.Sdk.Arp;
+using Ryujinx.Horizon.Sdk.Arp.Detail;
+using Ryujinx.Horizon.Sdk.Sf.Hipc;
+using Ryujinx.Horizon.Sdk.Sm;
+
+namespace Ryujinx.Horizon.Arp
+{
+    class ArpIpcServer
+    {
+        private const int ArpRMaxSessionsCount = 16;
+        private const int ArpWMaxSessionsCount = 8;
+        private const int MaxSessionsCount = ArpRMaxSessionsCount + ArpWMaxSessionsCount;
+
+        private const int PointerBufferSize = 0x1000;
+        private const int MaxDomains = 24;
+        private const int MaxDomainObjects = 32;
+        private const int MaxPortsCount = 2;
+
+        private static readonly ManagerOptions _managerOptions = new(PointerBufferSize, MaxDomains, MaxDomainObjects, false);
+
+        private SmApi _sm;
+        private ServerManager _serverManager;
+        private ApplicationInstanceManager _applicationInstanceManager;
+
+        public IReader Reader { get; private set; }
+        public IWriter Writer { get; private set; }
+
+        public void Initialize()
+        {
+            HeapAllocator allocator = new();
+
+            _sm = new SmApi();
+            _sm.Initialize().AbortOnFailure();
+
+            _serverManager = new ServerManager(allocator, _sm, MaxPortsCount, _managerOptions, MaxSessionsCount);
+
+            _applicationInstanceManager = new ApplicationInstanceManager();
+
+            Reader reader = new(_applicationInstanceManager);
+            Reader = reader;
+
+            Writer writer = new(_applicationInstanceManager);
+            Writer = writer;
+
+            _serverManager.RegisterObjectForServer(reader, ServiceName.Encode("arp:r"), ArpRMaxSessionsCount);
+            _serverManager.RegisterObjectForServer(writer, ServiceName.Encode("arp:w"), ArpWMaxSessionsCount);
+        }
+
+        public void ServiceRequests()
+        {
+            _serverManager.ServiceRequests();
+        }
+
+        public void Shutdown()
+        {
+            _applicationInstanceManager.Dispose();
+            _serverManager.Dispose();
+        }
+    }
+}