[FR]: allow user to set custom alert sounds

[Chiitoo]

Contact Details (e.g. Tox ID or email)

No response

Feature Description

I have been using custom sounds for my builds of qTox since ages past, but currently they need to be set at build-time.

It would be nice for users to be able to set these themselves, via settings, though at first I suppose it could work similar to custom theme colours where the file is sourced from certain places, if existing.

Contribution

• I would like to contribute to this feature