* Haydn: Part 1

Based on my reverse of audio 11.0.0.

As always, core implementation under LGPLv3 for the same reasons as for Amadeus.

This place the bases of a more flexible audio system while making audout & audin accurate.

This have the following improvements:
- Complete reimplementation of audout and audin.
- Audin currently only have a dummy backend.
- Dramatically reduce CPU usage by up to 50% in common cases (SoundIO and OpenAL).
- Audio Renderer now can output to 5.1 devices when supported.
- Audio Renderer init its backend on demand instead of keeping two up all the time.
- All backends implementation are now in their own project.
- Ryujinx.Audio.Renderer was renamed Ryujinx.Audio and was refactored because of this.

As a note, games having issues with OpenAL haven't improved and will not
because of OpenAL design (stopping when buffers finish playing causing
possible audio "pops" when buffers are very small).

* Update for latest hexkyz's edits on Switchbrew

* audren: Rollback channel configuration changes

* Address gdkchan's comments

* Fix typo in OpenAL backend driver

* Address last comments

* Fix a nit

* Address gdkchan's comments

* audio: Cleanup SoundIO and fix OpenAL issue

* fix tabs by spaces

* Fix extra spaces

* Fix SoundIO.cs

* Fix ContainsAudioOutBuffer

* audout: Implement GetAudioOutBufferCount, GetAudioOutPlayedSampleCount and FlushAudioOutBuffers

This PR implement audout service calls:
- GetAudioOutBufferCount
- GetAudioOutPlayedSampleCount
- FlushAudioOutBuffers

The RE calls just give some hints about no extra checks.
Since we use a totally different implementation because of our backend, I can't do something better for now.

SetAudioOutVolume and GetAudioOutVolume are fixed too by set/get the volume of the current opened track, previous implementation was wrong.

This fix #1133, fix #1258 and fix #1519.

Thanks to @jduncanator for this help during the implementation and all his precious advices.

* Fix some debug leftovers

* Address jD feedback

Changes:

    Implement software surround downmixing (fix #796).
    Fix a crash when no audio renderer were created when stopping emulation.

NOTE: This PR also disable support of 5.1 surround on the OpenAL backend as we cannot detect if the hardware directly support it. (the downmixing applied by OpenAL on Windows is terribly slow)

* Fix a crash when closing the main Ui

Also make sure to dispose the OpenAL context to not leak memory when
unloading the emulation context.

* Improve keys and 'game already running' dialogs

* Make sure to dispose the page table and ThreadContext

Less memory leaks!

* Fix tests

* Address gdk's comments

* Name all threads

Close #874

* use ThreadName instead of ThreadId in Logging

* audout:u: Implement SetAudioOutVolume and GetAudioOutVolume

- Implementation of `audout:u` SetAudioOutVolume and GetAudioOutVolume (checked with RE).
- Add Get and Set for Volume into audio backends.
- Cleanup of all audio backends to follow the `IAalOutput` structure and .NET standard.
- Split OpenAL backend into 2 files for consistency.

* Address comments

* Fix the volume calculation

* Fix typos

* Remove unneeded using statements

* Enforce var style more

* Remove redundant qualifiers

* Fix some indentation

* Disable naming warnings on files with external enum names

* Fix build

* Mass find & replace for comments with no spacing

* Standardize todo capitalization and for/if spacing

* Audio: Select a shared audio device by default

This ensures that a non-raw audio device is selected wherever possible.

* Audio: Resolve libsoundio version mismatch between bindings and binaries

It turns out we were using bindings generated with libsoundio 1.1.0 git source, but the binaries we were using were built from master git source. I've rebuilt both binaries and bindings to ensure they are version matched.

This should resolve all outstanding issues with libsoundio (including the Linux segfault issue, and the "cannot open device" Windows issue).

* Audio: Reformat MarshalExtensions

* Resolve code indentation issues

We need to signal the guest process when buffers are released to avoid a softlock.