[Applets] Add initial stuff

include/applets/applet.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include "helpers.hpp"
+#include "memory.hpp"
+#include "result/result.hpp"
+
+class AppletBase {
+	Memory& mem;
+
+  public:
+	// Called by APT::StartLibraryApplet and similar
+	virtual Result::HorizonResult start() = 0;
+	virtual void reset() = 0;
+
+	AppletBase(Memory& mem) : mem(mem) {}
+};