Haydn: Part 1 (#2007)

* 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

Ryujinx.Audio.Renderer/Utils/SpanMemoryManager.cs

@@ -1,60 +0,0 @@
-//
-// Copyright (c) 2019-2021 Ryujinx
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-//
-
-using System;
-using System.Buffers;
-using System.Runtime.InteropServices;
-
-namespace Ryujinx.Audio.Renderer.Utils
-{
-    public sealed unsafe class SpanMemoryManager<T> : MemoryManager<T>
-        where T : unmanaged
-    {
-        private readonly T* _pointer;
-        private readonly int _length;
-
-        public SpanMemoryManager(Span<T> span)
-        {
-            fixed (T* ptr = &MemoryMarshal.GetReference(span))
-            {
-                _pointer = ptr;
-                _length = span.Length;
-            }
-        }
-
-        public override Span<T> GetSpan() => new Span<T>(_pointer, _length);
-
-        public override MemoryHandle Pin(int elementIndex = 0)
-        {
-            if (elementIndex < 0 || elementIndex >= _length)
-            {
-                throw new ArgumentOutOfRangeException(nameof(elementIndex));
-            }
-
-            return new MemoryHandle(_pointer + elementIndex);
-        }
-
-        public override void Unpin() { }
-
-        protected override void Dispose(bool disposing) { }
-
-        public static Memory<T> Cast<TFrom>(Memory<TFrom> memory) where TFrom : unmanaged
-        {
-            return new SpanMemoryManager<T>(MemoryMarshal.Cast<TFrom, T>(memory.Span)).Memory;
-        }
-    }
-}