[crossfire] Sounds

[Kevin Zheng]

On 1/17/21 1:38 AM, Nicolas Weeger wrote:
> The "sounds" repository contains various sounds for use with the clients.
> 
> Unfortunately many don't have a proper license attached (especially the old
> ones).
> 
> I therefore propose to remove files with an unknown origin, to (re)start with a
> clean state.

I think this proposal seems reasonable. This might also be a good 
opportunity to improve the quality of the default set of sounds.