feat(nix): refactor Searx configuration into separate module

- Moved Searx-related settings from `default.nix` and `nginx.nix` to a dedicated `searx.nix` module for improved modularity and maintainability.
- Updated references and ACME certificate configuration to align with the new structure.
- Simplifies management of Searx service and its associated secrets.

systems/x86_64-linux/sgx/searx.nix

@@ -0,0 +1,34 @@
+{ pkgs, config, ... }:
+{
+  sops.secrets."searx/secret_key".sopsFile = ../../../.secrets/sgx/searx.yaml;
+
+  services.searx = {
+    enable = true;
+    configureNginx = true;
+    domain = "search.hoyer.world";
+    uwsgiConfig = {
+      http = ":8081";
+    };
+    settings = {
+      server = {
+        secret_key = config.sops.secrets."searx/secret_key".path;
+      };
+    };
+  };
+
+  services.nginx.virtualHosts = {
+    "search.hoyer.world" = {
+      enableACME = false;
+      useACMEHost = "search.hoyer.world";
+      forceSSL = true;
+    };
+  };
+
+  security.acme.certs = {
+    "internal.hoyer.world" = {
+      extraDomainNames = [
+        "search.hoyer.world"
+      ];
+    };
+  };
+}