Move audio playback to the "front-end"

[SpookyBoy99]

hello.mp3 and goodbye.mp3 are played via the "back-end" node instance, requiring a package that spawns a process for playing the audio (such as aplay or mpg123). The front-end of electron has built-in support for playing audio and does not require any additional dependencies. I suggest using an ipc event to trigger audio playback from the electron thread.