Support Peer with no connection

[lumtis]

Is your feature request related to a problem? Please describe.
Support validator peer with no connection for ignite/cli#2220

Describe the solution you'd like

Adding none or a similar name in Peer

spn/proto/launch/genesis_validator.proto

Line 18 in 2243743

message Peer {

message Peer {
  string id = 1;

  oneof connection {
    string tcpAddress = 2;
    HTTPTunnel httpTunnel = 3;
    [EMPTY] none = 4; // empty struct
  }

  message HTTPTunnel {
    string name = 1;
    string address = 2;
  }
}

We still require to provide node ID which may not have practical usage for the launch

Describe alternatives you've considered

Allowing zero value for Peer. On the client, if id == "" the validator has no exposed peer