Proposal to Add nkey Support to the Account CRD

[yunerou]

What motivated this proposal?

nkey is one of the widely-used authentication methods, (same with username/password or TLS). There is a need for a simpler configuration mechanism through the Account CRD.
Currently, nkey values are directly embedded as plain strings within stream and consumer CRDs, making them difficult to secure. To address this, storing these nkey values in a Secret should be supported.

What is the proposed change?

Introduce a new nkey field to the Account CRD, similar to existing fields like creds or tls.

Who benefits from this change?

No response

What alternatives have you evaluated?

No response