Transcribe speech to text offline with Whisper

- Allow server admin to configure offline speech to text model during
  initialization
- Use offline speech to text model to transcribe audio from clients
- Set offline whisper as default speech to text model as no setup api key reqd

pyproject.toml

@@ -75,6 +75,7 @@ dependencies = [
     "tzdata == 2023.3",
     "rapidocr-onnxruntime == 1.3.8",
     "stripe == 7.3.0",
+    "openai-whisper >= 20231117",
 ]
 dynamic = ["version"]