mtmd: qwen3 audio support (qwen3-omni and qwen3-asr)

The Qwen3 model now supports audio input through its `qwen3-omni-moe` (multimodal with vision and audio input) and `qwen3-asr` (audio speech recognition) versions. GGUF models for Qwen3-Omni (30B variants) and Qwen3-ASR (1.7B and 0.6B) are available on Hugging Face for community use.