fs.mitm: Get Title ID on fsp-srv init, Add worker to handle subinterfaces.

stratosphere/fs_mitm/source/fsmitm_worker.hpp

@@ -0,0 +1,11 @@
+#pragma once
+#include <switch.h>
+#include <stratosphere.hpp>
+
+class FsMitmWorker {
+    private:
+        static Result AddWaitableInternal(Handle *handles, size_t num_handles, u64 timeout);
+    public:
+        static void Main(void *arg);
+        static void AddWaitable(IWaitable *waitable);
+};