service: Add the es service

Adds the skeleton for the ETicket service based off the information on
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src/core/hle/service/es/es.h

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+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+namespace Service::SM {
+class ServiceManager;
+}
+
+namespace Service::ES {
+
+/// Registers all ES services with the specified service manager.
+void InstallInterfaces(SM::ServiceManager& service_manager);
+
+} // namespace Service::ES