move public/private wifi logic into its own module

systems/artemision/private-wifi.nix

@@ -0,0 +1,19 @@
+{ ... }:
+{
+  networking.nameservers = [
+    "9.9.9.9"
+    "1.1.1.1"
+    "192.168.76.1"
+  ];
+
+  services.resolved = {
+    enable = true;
+    dnssec = "false";
+    domains = [ "~." ];
+    fallbackDns = [
+      "1.1.1.1#one.one.one.one"
+      "1.0.0.1#one.one.one.one"
+    ];
+    dnsovertls = "true";
+  };
+}