Add support for WebRTC Auto Gain and Noise Suppression (#250)

## WebRTC Auto Gain & Noise Suppression
 
This PR adds support for WebRTC Auto Gain and Noise Suppression as previously implemented in the Wyoming Satellite project.
 
### What's New
 
Two new entities have been created a number slider for gain and another one for noise suppression. The processing happens inside of the `webrtc.py` file and is implemented in the `__main__.py` file's `process_audio` function. The slider for gain has a limit of 0-31 and noise suppression has a limit of 0-4.
 
The Auto Gain and Noise Suppression persist through restarts and are saved as preferences. The values are dynamically chnged without needing a restart.
 
CLI flags called `--mic-auto-gain` and `--mic-noise-suppression` have also been added.
 
>  When both values are 0, WebRTC processing is bypassed entirely with no performance overhead.

Closes #25 
 
### Testing
 
When saving the audio recorded by LVA there is a noticeable increase. The following two files have been recorded with similar audio being played through them with these results (Gain-31 and NS-4):
 
| Metric | With AGC+NS | Without |
|---|---|---|
| Max amplitude | 0.329 | 0.054 |
| RMS amplitude | 0.008905 | 0.002862 |
| Volume adjustment needed | 3.034x | 13.479x |
| Rough frequency | 916 Hz | 705 Hz |

.env.example

@@ -41,6 +41,12 @@ LVA_PULSE_COOKIE="/run/user/${LVA_USER_ID}/pulse/cookie"
 ### Audio output device (optional):
 # AUDIO_OUTPUT_DEVICE="default"
 
+### Mic Gain (optional) passed as an argument to LVA will overide the value in thepreferences file on boot but can be changed at runtime in Home Assistant:
+# MIC_AUTO_GAIN="0"
+
+### Mic Noise Suppression (optional) passed as an argument to LVA will overide the value in thepreferences file on boot but can be changed at runtime in Home Assistant:
+# MIC_NOISE_SUPPRESSION="0"
+
 ### Enable thinking sound (optional):
 # ENABLE_THINKING_SOUND="1"