Migrate data-mesher to clan service

clanServices/data-mesher/admin.nix

@@ -0,0 +1,29 @@
+{
+  lib,
+  config,
+  settings,
+  ...
+}:
+{
+
+  services.data-mesher.initNetwork =
+    let
+      # for a given machine, read it's public key and remove any new lines
+      readHostKey =
+        machine:
+        let
+          path = "${config.clan.core.settings.directory}/vars/per-machine/${machine}/data-mesher-host-key/public_key/value";
+        in
+        builtins.elemAt (lib.splitString "\n" (builtins.readFile path)) 1;
+    in
+    {
+      enable = true;
+      keyPath = config.clan.core.vars.generators.data-mesher-network-key.files.private_key.path;
+
+      tld = settings.network.tld;
+      hostTTL = settings.network.hostTTL;
+
+      # admin and signer host public keys
+      signingKeys = builtins.map readHostKey (builtins.attrNames settings.bootstrapNodes);
+    };
+}