Implement proc_ui.rpl + stub SYSSwitchToEManual() to avoid softlocks

- Full reimplementation of proc_ui.rpl with all 19 exports
- Foreground/Background messages now go to the coreinit system message queue as they should (instead of using a hack where proc_ui receives them directly)
- Add missing coreinit API needed by proc_ui: OSGetPFID(), OSGetUPID(), OSGetTitleID(), __OSCreateThreadType()
- Use big-endian types in OSMessage
- Flesh out the stubs for OSDriver_Register and OSDriver_Unregister a bit more since we need to call it from proc_ui. Similiar small tweaks to other coreinit API
- Stub sysapp SYSSwitchToEManual() and _SYSSwitchToEManual() in such a way that they will trigger the expected background/foreground transition, avoiding softlocks in games that call these functions

src/Cafe/OS/libs/nn_olv/nn_olv.cpp

@@ -9,6 +9,7 @@
 
 #include "Cafe/OS/libs/proc_ui/proc_ui.h"
 #include "Cafe/OS/libs/coreinit/coreinit_Time.h"
+#include "Cafe/OS/libs/coreinit/coreinit_Misc.h"
 
 namespace nn
 {
@@ -37,7 +38,7 @@ namespace nn
 		void StubPostAppReleaseBackground(PPCInterpreter_t* hCPU)
 		{
 			coreinit::OSSleepTicks(ESPRESSO_TIMER_CLOCK * 2); // Sleep 2s
-			ProcUI_SendForegroundMessage();
+			coreinit::StartBackgroundForegroundTransition();
 		}
 
 		sint32 StubPostApp(void* pAnyPostParam)