Add custom pm sysmodule

sysmodules/pm/source/service_manager.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <3ds/types.h>
+
+typedef struct ServiceManagerServiceEntry {
+    const char *name;
+    u32 maxSessions;
+    void (*handler)(void *ctx);
+    bool isGlobalPort;
+} ServiceManagerServiceEntry;
+
+typedef struct ServiceManagerNotificationEntry {
+    u32 id;
+    void (*handler)(u32 id);
+} ServiceManagerNotificationEntry;
+
+typedef struct ServiceManagerContextAllocator {
+    void* (*newSessionContext)(u8 serviceId);
+    void  (*freeSessionContext)(void *ctx);
+} ServiceManagerContextAllocator;
+
+Result ServiceManager_Run(const ServiceManagerServiceEntry *services, const ServiceManagerNotificationEntry *notifications, const ServiceManagerContextAllocator *allocator);