Highpass filter and external voices for non-English langs

[kercre123]

• Use highpass filter on mic data
  • This makes VAD far more accurate by reducing background noise
  • Also makes it work better from far away
• Use OpenAI voices on Vector for non-English languages
  • You can choose the voice in server settings
  • (libsoxr is required now)
• Re-add STT language in initial page
• Whisper.cpp fixes