proposal: add sensitivity feedback to the logs

The current implementation requires the user to predict and generate stimulus that should be ignored, and set the sensor sensitivity in advance. But after deployment, imperfections of that guesswork manifest as false positives.

The sound logs should indicate the db level that triggered the event as well as the peak level in that event. Motion logs should give the triggering value as well, for improved tuning.

This feature would also help troubleshoot bugs like https://github.com/guardianproject/haven/issues/261.

Start by locating the sound and motion sensor logging paths in the Android application, then trace how triggering and peak values are currently calculated. Reproduce a sound or motion event and inspect the emitted logs. Done means sound logs include the triggering and peak dB values, while motion logs include the triggering value.

Written by the indexing model from the issue text.