Bug: official Helm chart doesn't allow to pass custom NATS

[rangoo94]

Describe the bug

The Helm chart decides to include the NATS based on testkube-api.nats.enabled.

If someone wants to use external NATS service, there are 2 options now:

• Pass testkube-api.nats.secretName and testkube-api.nats.secretKey for the expected NATS service and keep testkube-api.nats.enabled: true
  • There will be still running NATS container, just unused
• Option 1, but with own Helm chart to avoid deploying unused NATS container

Expected behavior

• There should be an option to avoid NATS service, while still passing proper NATS credentials
• Optionally: there could be an option to pass NATS URI in plain text (like testkube-api.nats.uri)