Enable dual audio input channel (#334)

This PR adds the ability to choose the microphone stream that works best with a particular STT engine using the new dual audio input channel feature.

.env.example

@@ -54,6 +54,9 @@ LVA_PULSE_COOKIE="/run/user/${LVA_USER_ID}/pulse/cookie"
 ### Mic Noise Suppression (optional) passed as an argument to LVA will overide the value in the preferences file on boot but can be changed at runtime in Home Assistant:
 # MIC_NOISE_SUPPRESSION="0"
 
+### Number of mic channels to stream
+# AUDIO_INPUT_CHANNELS=2
+
 ### Enable thinking sound (optional):
 # ENABLE_THINKING_SOUND="1"