Add Docker daemon and service hardening configurations

- config/docker/daemon.json: Docker security hardening with logging limits and security options
- config/systemd/nginx.service.d/rate-limit.conf: Nginx resource limits and connection throttling
- Includes deployment instructions for container and service security

config/systemd/nginx.service.d/rate-limit.conf

@@ -0,0 +1,13 @@
+# Nginx Service Rate Limiting Configuration  
+# Deploy to: /etc/systemd/system/nginx.service.d/rate-limit.conf
+# 
+# Setup commands:
+#   sudo mkdir -p /etc/systemd/system/nginx.service.d
+#   sudo cp config/systemd/nginx.service.d/rate-limit.conf /etc/systemd/system/nginx.service.d/
+#   sudo systemctl daemon-reload
+#   sudo systemctl restart nginx
+
+[Service]
+# Limit nginx connections
+LimitNOFILE=65536
+LimitNPROC=4096