Enhance derp relay to verify enpoints are onboarded nodes.

[vishnoianil]

Describe the Problem Statement

Currently DERP relay relays the wireguard traffic based on the public key that a client/node used to register with derp relay. It doesn't verify if connected clients are onboarded with nexodus control plane. This leaves a possibility of DDoS attack on relay by connecting endpoints that are not onboarded to nexodus and relaying traffic between them.

Describe the Enhancement

We need to add a new API and watchers to get all the node details (public keys, endpoint info) from the nexodus control plane. This info will be used to deny the connection from the nodes that is not part of the nexodus network.

Alternate Solutions

No response

Additional context

No response