As it turns out, although Home Assistant itself works perfectly fine on
a Raspberry Pi, Piper and Whisper do not. They are _much_ too slow to
respond to voice commands.
This reverts commit 32666aa628.
Piper is the new text-to-speech service for Home Assistant. Whisper is
a speech-to-text service. Together, these services, which communicate
with Home Assistant via the Wyoming protocol, provide the speech
interface to the new Home Assistant Voice Assistant feature.