Polish KarlDNS production UI and docs

.env.example

@@ -1,6 +1,7 @@
 # Required for a public KarlDNS instance.
 DDNS_ADMIN_PASSWORD=change-me-long-random-admin-password
 DDNS_ADMIN_PATH=/admin
+DDNS_DASHBOARD_COOKIE_SECRET=change-me-long-random-cookie-signing-secret
 DDNS_PUBLIC_BASE_URL=https://karldns.de
 DDNS_HOSTNAME_SUFFIX=karldns.de
 
@@ -23,6 +24,7 @@ DDNS_TTL=60
 # DDNS_RATE_LIMIT_PER_MINUTE=60
 # DDNS_ADMIN_RATE_LIMIT_PER_MINUTE=20
 # DDNS_MAX_REQUEST_BODY_BYTES=16384
+# DDNS_REDACTED_ACCESS_LOG=0
 # DDNS_CLEANUP_CHALLENGE_HOURS=72
 # DDNS_CLEANUP_UNUSED_ACCOUNT_HOURS=1080
 # DDNS_CLEANUP_EVENT_HISTORY_HOURS=4320