audio_core: Add OpenAL audio backend support

- Add complete OpenAL sink implementation with robust error handling
- Support for device enumeration using ALC extensions
- Implement dummy streams for graceful degradation when OpenAL fails
- Add proper audio threading and buffer management
- Include comprehensive logging and diagnostic information
- Add stream limits and retry mechanisms for stability

Additional changes:
- Add ENABLE_OPENAL CMake option and OpenAL dependency management
- Include openal-soft in vcpkg dependencies
- Add OpenAL to audio engine settings enum

The OpenAL backend provides an alternative audio solution alongside
existing Cubeb and SDL2 backends, with enhanced device compatibility
and improved error recovery mechanisms.

Signed-off-by: Zephyron <zephyron@citron-emu.org>

CMakeLists.txt

@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2018 yuzu Emulator Project
+# SPDX-FileCopyrightText: 2025 citron Emulator Project
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 cmake_minimum_required(VERSION 3.22)
@@ -44,6 +45,8 @@ option(CITRON_USE_QT_WEB_ENGINE "Use QtWebEngine for web applet implementation"
 
 option(ENABLE_CUBEB "Enables the cubeb audio backend" ON)
 
+option(ENABLE_OPENAL "Enables the OpenAL audio backend" ON)
+
 option(USE_DISCORD_PRESENCE "Enables Discord Rich Presence" OFF)
 
 option(CITRON_TESTS "Compile tests" "${BUILD_TESTING}")