Requirements [here][1]:
> OK:
> server_url: headscale.com, base: clients.headscale.com
> server_url: headscale.com, base: headscale.net
>
> Not OK:
> server_url: server.headscale.com, base: headscale.com
>
> Essentially we have to prevent the possibility where the headscale
> server has a URL which can also be assigned to a node.
>
> So for the Not OK scenario:
>
> if the server is: server.headscale.com, and a node joins with the name
> server, it will be assigned server.headscale.com and that will break
> the connection for nodes which will now try to connect to that node
> instead of the headscale server.
Fixes#2210
[1]: https://github.com/juanfont/headscale/issues/2210#issuecomment-2488165187
this commit changes and streamlines the dns_config into a new
key, dns. It removes a combination of outdates and incompatible
configuration options that made it easy to confuse what headscale
could and could not do, or what to expect from ones configuration.
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
