After doing a little more reading up on the Opus codec, it turns out
that the multistream API that is part of libopus can handle regular
packets. Regular packets are just a degenerate case of multistream Opus
packets, and all that's necessary is to pass the number of streams as 1
and  provide a basic channel mapping, then everything works fine for
that case.

This allows us to get rid of the need to use both APIs in the future
when implementing multistream variants in a follow-up PR, greatly
simplifying the code that needs to be written.

service/audio/hwopus: Move decoder state to its own class

kernel/scheduler: Pass in system instance in constructor

shader_ir: Remove "extras" from the MetaTexture

gl_rasterizer_cache: Create texture views for array discrepancies

audio_core/cubeb_sink: Convert _MSC_VER ifdefs to _WIN32

gl_rasterizer: Minor logger changes

core/settings: Log more setting values

 yuzu_cmd/config: Silent implicit cast warning 

This behavior also needs to be visible for MinGW builds as well.

kernel/hle_ipc: Convert std::shared_ptr IPC header instances to std::optional

video_core/gpu_thread: Silence a -Wreorder warning

video_core/gpu: Make GPU's destructor virtual

maxwell_to_vk: Initial implementation

dma_pusher: Store command_list_header by copy

Instead of holding a reference that will get invalidated by
dma_pushbuffer.pop(), hold it as a copy. This doesn't have any
performance cost since CommandListHeader is 8 bytes long.

There's no real need to use a shared lifetime here, since we don't
actually expose them to anything else. This is also kind of an
unnecessary use of the heap given the objects themselves are so small;
small enough, in fact that changing over to optionals actually reduces
the overall size of the HLERequestContext struct (818 bytes to 808
bytes).

For whatever bizarre reason, Apple only made a few of std::optional's
member functions available on newer SDK versions. Given we can't even
run yuzu on macOS, and we keep the builder around to ensure that it
always at least compiles on macOS, we can bump this up a version.

kernel/shared_memory: Get rid of the use of global accessor functions within Create()

This makes the class much more flexible and doesn't make performing
copies with classes that contain a bitfield member a pain.

Given BitField instances are only intended to be used within unions, the
fact the full storage value would be copied isn't a big concern (only
sizeof(union_type) would be copied anyways).

While we're at it, provide defaulted move constructors for consistency.

This function didn't have a definition, so we can remove it to prevent
accidentally attempting to use it.

Moves the data members to satisfy the order they're declared as in the
constructor initializer list.

Silences a -Wreorder warning.

Because of the recent separation of GPU functionality into sync/async
variants, we need to mark the destructor virtual to provide proper
destruction behavior, given we use the base class within the System
class.

Prior to this, it was undefined behavior whether or not the destructor
in the derived classes would ever execute.

web_browser: Add shortcut to Enter key to exit applet

kernel/client_session, kernel/server_session: Make data members private

yuzu: add a hotkey to switch between undocked and docked mode

service/audio/audout_u: Only actually stop the audio stream in StopAudioOut if the stream is playing

Asynchronous GPU command processing

Moves the non-multistream specific state to its own class. This will be
necessary to support the multistream variants of opus decoding.

This indicates the entropy coder's final range.

This will be utilized by more than just that class in the future. This
also renames it from OpusHeader to OpusPacketHeader to be more specific
about what kind of header it is.

Makes it impossible to violate the ODR, as well as providing a place for
future changes.

service/audio/audout_u: Only actually stop the audio stream in StopAudioOut if the stream is playing

The service itself only does further actions if the stream is playing.
If the stream is already stopped, then it just exits successfully.

 gl_rasterizer_cache: Move format conversion functions to their own file 

core/hle/ipc: Remove unnecessary includes