frontend: Add an option for a chime instead of synthetic speech for vehicle connection loss

[ArturoManzoli]

Current behaviour

Cockpit uses speech to communicate many events to the user and sometimes is hard to differentiate them on a noisy environment.

Expected or desired behaviour

Cockpit should allow the user to select a chime, joy/phone vibration or other event to communicate vehicle connection loss/regain.

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.