fs.mitm: WIP LayeredFS impl (NOTE: UNUSABLE ATM)

Also greatly refactors libstratosphere, and does a lot of other things.
There is a lot of code in this one.

stratosphere/pm/source/pm_shell.cpp

@@ -1,4 +1,5 @@
 #include <switch.h>
+#include <stratosphere.hpp>
 #include "pm_registration.hpp"
 #include "pm_resource_limits.hpp"
 #include "pm_shell.hpp"