hos: change initialization API

This was needed to make stratosphere buildable with debugging on.

os:: assertions rely on GetCurrentThread() working, and this requires
the global os resource manager to be constructed. However, __appInit executes
before global constructors. We now require that hos::InitializeForStratosphere()
be called before anything else is done. This initializes the os resource manager,
sets the hos version for libnx, and may do more things in the future.

TODO: Consider replacing __appInit/__appExit with ams:: namespace functions in general,
and wrap them so that we guarantee hos::InitializeForStratosphere is called first, and
generally ensure a consistent stratosphere environment.

stratosphere/sm/source/sm_main.cpp

@@ -70,7 +70,7 @@ void __libnx_initheap(void) {
 }
 
 void __appInit(void) {
-    hos::SetVersionForLibnx();
+    hos::InitializeForStratosphere();
 
     /* We must do no service setup here, because we are sm. */
 }