fix(ingress): add some security headers

.socialgouv/config.json

 {
   "type": "static",
   "name": "archifiltre-site",
-  "subdomain": "archifiltre"
+  "subdomain": "archifiltre",
+  "annotations": {
+    "nginx.ingress.kubernetes.io/configuration-snippet": "more_set_headers \"Content-Security-Policy: default-src 'none'; connect-src 'self' https://*.gouv.fr; font-src 'self'; img-src 'self'; prefetch-src 'self' https://*.gouv.fr; script-src 'self' https://*.gouv.fr; frame-src 'self' https://*.gouv.fr; style-src 'self' 'unsafe-inline'\";\nmore_set_headers \"X-Frame-Options: deny\";\nmore_set_headers \"X-XSS-Protection: 1; mode=block\";\nmore_set_headers \"X-Content-Type-Options: nosniff\";"
+  }
 }