SRVKS-1222: Add section with Kourier and Istio diagrams

[ochromy]

Issue link:

• https://issues.redhat.com/browse/SRVKS-1222

Motivation:

• We need to include the ingress diagrams in the downstream Serverless docs.
  BUT
• The professional diagrams are not ready yet.
  THEREFORE
• We want to add the diagrams (along with the necessary context) to the developer preview docs and link to them in the downstream docs until the professional diagrams are available.

Contents:

• Modified downstream assembly (serving-kourier-istio-ingresses.adoc)
• Kourier and Istio diagrams in PNG format -> If necessary, I can either recreate them in the SVG format or ask around for the Draw.io originals. These were copied from an older gdoc draft (https://docs.google.com/document/d/1SYxOmlfwf-s7MTzOaeqoyWQuVWAq8EMocuMGyM3fZuc/edit?tab=t.0#heading=h.qbzflmdprtdi)

[openshift-ci-robot]

@ochromy: This pull request references SRVKS-1222 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the feature to target the "4.19.0" version, but no target version was set.

In response to this:

Issue link:

• https://issues.redhat.com/browse/SRVKS-1222

Motivation:

• We need to include the ingress diagrams in the downstream Serverless docs.
  BUT
• The professional diagrams are not ready yet.
  THEREFORE
• We want to add the diagrams (along with the necessary context) to the developer preview docs and link to them in the downstream docs until the professional diagrams are available.

Contents:

• Modified downstream assembly (serving-kourier-istio-ingresses.adoc)
• Kourier and Istio diagrams in PNG format -> If necessary, I can either recreate them in the SVG format or ask around for the Draw.io originals. These were copied from an older gdoc draft (https://docs.google.com/document/d/1SYxOmlfwf-s7MTzOaeqoyWQuVWAq8EMocuMGyM3fZuc/edit?tab=t.0#heading=h.qbzflmdprtdi)

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: ochromy

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[netlify]

✅ Deploy Preview for jazzy-shortbread-5f62b7 ready!

Name	Link
🔨 Latest commit	f6e9d83
🔍 Latest deploy log	https://app.netlify.com/sites/jazzy-shortbread-5f62b7/deploys/67f5111b545e6b0008b0c19e
😎 Deploy Preview	https://deploy-preview-121--jazzy-shortbread-5f62b7.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.