[WIP] NE-2743: Support centralized TLS security profiles for CDO metrics

The CoreDNS DaemonSet's kube-rbac-proxy sidecar now derives its TLS
cipher suites and minimum TLS version dynamically from the cluster-wide
APIServer TLS security profile instead of using hardcoded values. The
operator watches the APIServer "cluster" resource and reconciles when
the TLS policy changes.

TLS curves/groups are not explicitly passed to kube-rbac-proxy (it has
no --tls-curves flag); Go 1.25's crypto/tls defaults already include
X25519MLKEM768 (ML-KEM post-quantum) when CurvePreferences is unset,
which aligns with the CIO approach.

Assisted with Claude

Author: Thealisyed

manifests/0000_70_dns-operator_02-deployment-ibm-cloud-managed.yaml

@@ -49,7 +49,8 @@ spec:
       - args:
         - --logtostderr
         - --secure-listen-address=:9393
-        - --tls-cipher-suites=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_RSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
+        - --tls-cipher-suites=TLS_AES_128_GCM_SHA256,TLS_AES_256_GCM_SHA384,TLS_CHACHA20_POLY1305_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
+        - --tls-min-version=VersionTLS12
         - --upstream=http://127.0.0.1:60000/
         - --tls-cert-file=/etc/tls/private/tls.crt
         - --tls-private-key-file=/etc/tls/private/tls.key

manifests/0000_70_dns-operator_02-deployment.yaml

@@ -66,7 +66,8 @@ spec:
         args:
         - --logtostderr
         - --secure-listen-address=:9393
-        - --tls-cipher-suites=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_RSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
+        - --tls-cipher-suites=TLS_AES_128_GCM_SHA256,TLS_AES_256_GCM_SHA384,TLS_CHACHA20_POLY1305_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
+        - --tls-min-version=VersionTLS12
         - --upstream=http://127.0.0.1:60000/
         - --tls-cert-file=/etc/tls/private/tls.crt
         - --tls-private-key-file=/etc/tls/private/tls.key