Kernel: Fix a warning introduced with ResourceLimit, and remove the fallback code to prevent it from happening again.

Implemented svcs GetResourceLimit, GetResourceLimitCurrentValues and GetResourceLimitLimitValues.

Note that the resource limits do not currently keep track of used objects, since we have no way to distinguish between an object created by the application, and an object created by some HLE module once we're inside Kernel::T::Create.

This has been obsoleted by the field in Process.

During normal operation, a thread waiting on an WaitObject and the
object hold mutual references to each other for the duration of the
wait.

If a process is forcefully terminated (The CTR kernel has a SVC to do
this, TerminateProcess, though no equivalent exists for threads.) its
threads would also be stopped and destroyed, leaving dangling pointers
in the WaitObjects.

The solution is to simply have the Thread remove itself from WaitObjects
when it is stopped. The vector of Threads in WaitObject has also been
changed to hold SharedPtrs, just in case. (Better to have a reference
cycle than a crash.)

It was only being used in two places, where it was replaced by a local
constant.

- ReleaseNextThread->WakeupNextThread
- ReleaseAllWaitingThreads->WakeupAllWaitingThreads.

- Separate wait checking from waiting the current thread
- Resume thread when wait_all=true only if all objects are available at once
- Set output to correct wait object index when there are duplicate handles

This handle manager more closely mirrors the behaviour of the CTR-OS
one. In addition object ref-counts and support for DuplicateHandle have
been added.

Note that support for DuplicateHandle is still experimental, since parts
of the kernel still use Handles internally, which will likely cause
troubles if two different handles to the same object are used to e.g.
wait on a synchronization primitive.

This boots a few (mostly Nintendo 1st party) games further.

The savedata for each game is stored in /savedata/<ProgramID> for NCCH files. ELF files and 3DSX files use the folder 0 because they have no ID information

Got rid of the code duplication in File and Directory

Files that deal with the host machine's file system now live in DiskFile, similarly for directories and DiskDirectory and archives with DiskArchive.

FS_U: Use the correct error code when a file wasn't found

This is a first step at fixing the conceptual insanity that is our
handling of service and IPC calls. For now, interfaces still directly
derived from Session because we don't have the infrastructure to do it
properly. (That is, Processes and scheduling them.)