feat: tune PGSQL on sectracker.nixpkgs.lahfa.xyz

According to the specs of the VM.

staging/sectracker.nix

@@ -15,6 +15,35 @@ in
     recommendedGzipSettings = true;
     recommendedOptimisation = true;
   };
+  services.postgresql = {
+    enableJIT = true;
+    settings = {
+      # DB Version: 15
+      # OS Type: linux
+      # DB Type: dw
+      # Total Memory (RAM): 16 GB
+      # CPUs num: 8
+      # Data Storage: hdd
+
+      max_connections = 40;
+      shared_buffers = "4GB";
+      effective_cache_size = "12GB";
+      maintenance_work_mem = "2GB";
+      checkpoint_completion_target = "0.9";
+      wal_buffers = "16MB";
+      default_statistics_target = "500";
+      random_page_cost = "4";
+      effective_io_concurrency = "2";
+      work_mem = "13107kB";
+      huge_pages = "off";
+      min_wal_size = "4GB";
+      max_wal_size = "16GB";
+      max_worker_processes = "8";
+      max_parallel_workers_per_gather = "4";
+      max_parallel_workers = "8";
+      max_parallel_maintenance_workers = "4";
+    };
+  };
   security.acme.acceptTerms = true;
   security.acme.defaults.email = obfuscate "zyx.afhal@emca-cilbup";
   networking.firewall.allowedTCPPorts = [