feat(eventbus): add exotic jetstream support

[gokulav137]

Add support for exotic jetstream eventbus

Resolves #2462

apiVersion: argoproj.io/v1alpha1
kind: EventBus
metadata:
  name: default
spec:
  jetstreamExotic:
      url: nats://xxxxx:xxx
      accessSecret:
        name: my-secret-name
        key: secret-key
      streamConfig: ""

Tested end to end

• created a nats jetstream using helm charts in a different namespace
• created a webhook eventsource
• created a sensor with email trigger
• sent a post request and validated that email was received

Checklist:

• My organization is added to USERS.md.

[whynowy]

LGTM, thanks!