Set up Atuin server and client

nix/system/network.nix

@@ -2,7 +2,7 @@
   networking = {
     hostName = "eve-psr-nix0";
     firewall = {
-      allowedTCPPorts = [ 22 80 443 ];
+      allowedTCPPorts = [ 22 80 443 7860 ];
       allowedUDPPorts = [ 22 80 443 53 1194 ];
       trustedInterfaces = [ "tun0" ];
     };