Remove split dns

I do not think this works when there are multiple sources holding the
dns records. The dns split should point to a server we have access to,
which can route the dns to another service in the network. Exposing
essentially some private dns. Not contend with a public dns record, as I
tried to do.

I think. This might become more relevant later...

values/headscale/values/values.yaml

@@ -20,14 +20,10 @@ env:
   # -- Node IPv6 prefixes
   HEADSCALE_PREFIXES_V6: "fd7a:115c:a1e0::/48"
 
-  # -- List of DNS servers to expose to clients.
-  HEADSCALE_DNS_NAMESERVERS_GLOBAL: "1.1.1.1 1.0.0.1"
-  HEADSCALE_DNS_NAMESERVERS_SPLIT: |
-    {
-      "oceanbox.io": ["100.100.100.100", "1.1.1.1"]
-    }
   # -- Whether to use [MagicDNS](https://tailscale.com/kb/1081/magicdns/).
   HEADSCALE_DNS_MAGIC_DNS: "true"
+  # -- List of DNS servers to expose to clients.
+  HEADSCALE_DNS_NAMESERVERS_GLOBAL: "1.1.1.1 1.0.0.1"
 
   HEADSCALE_DERP_URLS: "https://controlplane.tailscale.com/derpmap/default"
   HEADSCALE_DERP_AUTO_UPDATE_ENABLED: "true"