Change default bind_address of http/tcp/stream to include ipv6?

[jreusch]

I was at a friends home and the snapcast app worked flawlessly. Coming back to my setup the app reported something about connection problems... I could not figure it out, the auto discovered(!) hostname was right and i could access the 1780 port of this hostname. Digging deeper with netstat on the snapserver i realized it's because its bound to 0.0.0.0 (ipv4 only) as default.

So changing bind_to_address in the http/tcp/stream section to :: (as opposed to the 0.0.0.0 default setting) did the trick.

That's why i'd suggest to change in server_settings.hpp the default to that one, as we have 2022 and ipv6 @home is not so uncommon quite anymore and this maybe helps other folks of having a nice out of the box behavior of snapcast :)

I know this would break devices where this setting is currently left on default and which do not have ipv6 stack loaded. But those most likely are more custom ones, as even default raspbian has ipv6 available since the early days. What do you think?