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/common/OSCommon.cpp

@@ -221,5 +221,5 @@ void osLib_load()
 	nsyskbd::nsyskbd_load();
 	swkbd::load();
 	camera::load();
-	procui_load();
+	proc_ui::load();
 }