[FEATURE]Add doc/example for adding an egress gateway

[longmuir]

Is this the right place to submit this?

• This is not a question about how to use the sail-operator

Feature Description

Though an Egress Gateway is optional, unlike Istio's demo profile or Maistra.io's operator, the sail operator does not automatically create an Egress for users. Though this is intentional, it creates an onboarding gap for users (as reported by a customer). It could be resolved with an example configuration for an Egress gateway that is documented, to bring users to a similar point that they would be with the demo profile or Maistra operator.

Additional Information

No response

[fjglira]

@pbajjuri20 can you take a look at this? This is a good first issue. You can follow the upstream guides and add the docs sections to deploy a working egress gateway with sail operator

[pbajjuri20]

Sure, will work on it.