Write up documentation the new ingress functionality

## WHY
Why is this change being made?
As of [#251](https://github.com/project-codeflare/codeflare-sdk/pull/251) being merged currently there is no documentation on how to properly use `ingress_options` and `ingress_domain` and for what types of clusters.
## WHAT
What is being asked for?
Write up documentation on how to correctly use these new fields