Closes #1904

Moved the HLE command buffer translation task to ServerSession instead of the HLE handler superclass.

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.

Further implementation will happen in a future commit.

Fixes a regression.

The error code was taken from the 3DS kernel.

Split SessionRequestHandler::HandleSyncRequest into HandleSyncRequest, TranslateRequest and HandleSyncRequestImpl.

HandleSyncRequest now takes care of calling the command buffer translate function before actually invoking the command handler for HLE services.

KServerPorts now have an HLE handler "template", which is inherited by all ServerSessions created from it.

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.

Sessions and Ports are now detached from each other.
HLE services are handled by means of a SessionRequestHandler class, Interface now inherits from this class.
The File and Directory classes are no longer kernel objects, but SessionRequestHandlers instead, bound to a ServerSession when requested.
File::OpenLinkFile now creates a new session pair and binds the File instance to it.

Pass the triggering ServerSession to the HLE command handler to differentiate which session caused the request.

Kernel/HLE: Service::Interface no longer inherits from any Kernel object, and is now its own standalone class.

Interface is now used by aggregation in ClientPort, to forward service commands to their HLE implementation if needed.

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

Related to #1904

This makes clang-format useful on those.

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