ops/nixos: create permanent quotesdb user

Stop relying on DynamicUser because it messes a bit with postgres' auth.

ops/nixos/lib/quotes.bfob.gg.nix

@@ -75,6 +75,12 @@ in
       }];
     };
 
+    users.users.quotesdb = {
+      isSystemUser = true;
+      group = "nginx";
+    };
+    users.groups.quotesdb = {};
+
     systemd.services.quotesdb = {
       wantedBy = [ "multi-user.target" ];
       after = [ "network.target" ];
@@ -86,7 +92,7 @@ in
         EnvironmentFile = secrets.quotesdb.environment;
         RuntimeDirectory = "quotesdb";
         ExecStart = "${pkg}/bin/quotes --workers 3 --bind unix:${sock}";
-        DynamicUser = true;
+        User = "quotesdb";
         Group = "nginx";
         UMask = "0007";
       };