Change gRPC CipherSuite to be CNSA compliant

[nathanklick]

The configured gRPC cipher suites allow negotiation of TLS_RSA_WITH_AES_256_GCM_SHA384 which is not a CNSA compliant cipher suite. We should use TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 instead.

NettyServerManager.java (lines 102-105):

List<String> ciphers = Arrays.asList(
	"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
	"TLS_RSA_WITH_AES_256_GCM_SHA384"
);

Proposed Changes:

List<String> ciphers = Arrays.asList(
	"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
	"TLS_DHE_RSA_WITH_AES_256_GCM_SHA384"
);

[anighanta]

fixed here