Add a class that implements OSS (Open Sound System)

[ozguronsoy]

• Should derive from the NativeAudio class.
• Should at least implement device enumeration, rendering, and capturing.
• Should only be available for the platforms that support OSS.
• Add OSS to the AudioAPI enum for supported platforms and implement the API selection in the Audio class.
• link the OSS library (-lossaudio) in the CMake file if necessary.