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.

* pgl: add skeleton folder to stratosphere

* pgl: Add service interface for IShellInterface

* pgl: begin skeletoning shell service, implement two commands.

* pgl: Implement three more commands.

* pgl: implement bool tracking commands

* pgl: Implement TriggerApplicationSnapShotDumper

* pgl: implement InitializeProcessControlTask

* pgl: Implement pgl::srv::Initialize

* pgl: Implement main()

* pgl: Implement (Get)ShellEventObserver

* pgl: implement LaunchProgramFromHost, GetHostContentMetaInfo

* pgl: Implement ProcessControlTask

* settings: fix duplicate object name

* pgl: fix minor bugs in impl