v1.4.0: Merge pull request #4 from m5stack/dev

• Add whisper unit
• Add whisper-tiny model
• Add vad unit
• Add silero-vad model
• Add Qwen2.5-1.5B model
• Add depth_anything unit
• Add depth-anything model
• Optimize the initialization speed of the kws unit
• Optimize the initialization speed of the tts unit