Include waveform when sending voice messages (#1650)

- New `AudioLevelCalculator` that outputs dB0v rescaled to the [0;1] range.
- `VoiceRecorder` now stores the audio levels sampled while recording, then resamples them to 100 samples to use as waveform preview.
- Waveform data is carried all the way as a `List<Float>` and converted to `List<Int>` in the [0;1024] range as per matrix spec only before sending it.

libraries/voicerecorder/api/src/main/kotlin/io/element/android/libraries/voicerecorder/api/VoiceRecorderState.kt

@@ -38,9 +38,11 @@ sealed class VoiceRecorderState {
      *
      * @property file The recorded file.
      * @property mimeType The mime type of the file.
+     * @property waveform The waveform of the recording.
      */
     data class Finished(
         val file: File,
         val mimeType: String,
+        val waveform: List<Float>,
     ) : VoiceRecorderState()
 }