Closes #1904

The implementation is based on reverse engineering of the 3DS's kernel.

A mutex holder's priority will be temporarily boosted to the best priority among any threads that want to acquire any of its held mutexes.
When the holder releases the mutex, it's priority will be boosted to the best priority among the threads that want to acquire any of its remaining held mutexes.

This will be useful when implementing mutex priority inheritance.

Define a variable with the value of the sync timeout error code.

Use a boost::flat_map instead of an unordered_map to hold the equivalence of objects and wait indices in a WaitSynchN call.

Threads will now be awakened when the objects they're waiting on are signaled, instead of repeating the WaitSynchronization call every now and then.

The scheduler is now called once after every SVC call, and once after a thread is awakened from sleep by its timeout callback.

This new implementation is based off reverse-engineering of the real kernel.

See https://gist.github.com/Subv/02f29bd9f1e5deb7aceea1e8f019c8f4 for a more detailed description of how the real kernel handles rescheduling.

fixup!  Kernel/IPC: Use Ports and Sessions as the fundamental building block of Inter Process Communication.

 Kernel/IPC: Use Ports and Sessions as the fundamental building block of Inter Process Communication.

All handles obtained via srv::GetServiceHandle or svcConnectToPort are references to ClientSessions.
Service modules will wait on the counterpart of those ClientSessions (Called ServerSessions) using svcReplyAndReceive or svcWaitSynchronization[1|N], and will be awoken when a SyncRequest is performed.

HLE Interfaces are now ClientPorts which override the HandleSyncRequest virtual member function to perform command handling immediately.

3dsx and elf files default to system mode 2 (96MB allocated to the application).

This allows Home Menu to boot without modifications.
Closes #1849

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

This is part of an ongoing effort to implement support for multiple processes.

The code now properly configures the process image to match the loaded
binary segments (code, rodata, data) instead of just blindly allocating
a large chunk of dummy memory.

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.