Adding support for Picovoice Porcupine

[yonatan-mitmit]

feat: Add Porcupine hotword detection support

Add integration with the Porcupine hotword detection engine as an alternative to Snowboy. This change:

• Adds a new porcupine_wait_for_hot_word method that handles detection using the Picovoice Porcupine engine
• Extends the listen and _listen methods to accept a porcupine_configuration parameter
• Adds support for resampling audio to match Porcupine's required sample rate
• Implements frame buffering and processing using Porcupine's API
• Adds proper cleanup of Porcupine resources using try/finally

The configuration accepts parameters like access_key, library_path, model_path, keyword_paths,
keywords, and sensitivities, matching Porcupine's Python API requirements.

This provides users with a modern alternative to Snowboy for offline hotword detection,
as Snowboy is no longer actively maintained.

Dependencies:

• Requires the pvporcupine package to be installed