[helm] Adding support for gateways and leafnodes

[wallyqs]

Makes it possible to setup remote leafnodes and gateways as follows:

# Authentication setup
auth:
  enabled: true

  # Reference to the Operator JWT which will be mounted as a volume,
  # shared with the account server in this case.
  operatorjwt:
    configMap:
      name: operator-jwt
      key: KO.jwt

  # Public key of the System Account
  systemAccount: AAITGVORQ4VHOQ32A7XMEKUIDMJ5GSAYSUGOV6GZAVSQWYFAL72DIXLC

  resolver:
    type: URL
    url: "http://nats-account-server:9090/jwt/v1/accounts/"

nats:
  externalAccess: true
  logging:
    debug: true
    trace: true

leafnodes:
  enabled: true
  remotes:
    - url: tls://connect.ngs.global:7422
      credentials:
        secret:
          name: ngs-creds
          key: NGS.creds

gateway:
  enabled: true
  name: aws-useast2
  gateways:
    - name: euwest1
      url: tls://euwest1.aws.ngs.global:7522

# Add system credentials to the nats-box instance for example
natsbox:
  enabled: true

  credentials:
    secret:
      name: nats-sys-creds
      key: sys.creds

kubectl create secret generic ngs-creds --from-file ./.nkeys/creds/synadia/NGS/NGS.creds
helm install nats -f deploy-nats-gateways.yaml ./helm/charts/nats/

[matthiashanel]

Similar for cluster, can't do tls

[matthiashanel]

LGTM