Update Kueue documentation with TLS profile configuration examples and guidance.

Documentation to update:

• site/content/en/docs/installation.md or similar
• site/content/en/docs/reference/configuration.md

Content to add:

• Description of TLS configuration options
• Examples for common TLS profiles (Intermediate, Modern, Old)
• Security recommendations
• Troubleshooting guide for TLS issues

Example configuration:

apiVersion: config.kueue.x-k8s.io/v1beta2
kind: Configuration
webhook:   port: 9443
  minTLSVersion: "1.2"
  cipherSuites:     - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
    - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
metrics:   bindAddress: :8443
  minTLSVersion: "1.2"

Acceptance Criteria:

• Documentation covers all TLS configuration options
• Examples are tested and working
• Documentation passes review

Depends on: OCPKUEUE-456 (e2e tests complete)