Option to limit mapserver to localhost

[passw0rd123]

It would be nice to have a "host" option in the mapserver.json in addition to the port for limiting the application to a specific ip or localhost.

So if the mapserver is served via https by a reverseproxy, the unencrypted port wouldn't be exposed.

The needed change might be here and needs a new config option: https://github.com/minetest-mapserver/mapserver/blob/master/web/serve.go#L73C29-L73C62