Annotation conversion guidance for SSL and gRPC backend (upstream) services

[jnewfield]

Proposed changes

Problem: Add annotation conversion guidance for SSL and gRPC backend (upstream) services from Kubernetes Ingress-NGINX Controller to F5 NGINX Ingress Controller

Solution: Document conversions

Testing: I implemented F5 NGINX Ingress Controller annotations that are being documented in lab NIC environment to confirm they function as expected

Checklist

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• I have read the contributing guidelines
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• I have ensured my PR is targeting the main branch and pulling from my branch from my own fork
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• If the change involves potentially sensitive changes¹, I have assessed the possible impact
• If applicable, I have added tests that prove my fix is effective or that my feature works
• I have ensured that existing tests pass after adding my changes
• If applicable, I have updated README.md

Footnotes

1. Potentially sensitive changes include anything involving code, personally identify information (PII), live URLs or significant amounts of new or revised documentation. Please refer to our style guide for guidance about placeholder content. ↩

[ADubhlaoich]

I have removed the internal resource link from the PR description.

Could you reformat these snippets into a table?

There are some other small style conventions I can address as suggestions afterwards.

I would also like a different PR title, as the current one had no indication of what the context of the PR would be.

You might find our Commit messages guidelines useful.

[ADubhlaoich]

On further investigation, I'm curious what the intended use case for this specific detail is.

We have a Migrate from Ingress-NGINX Controller document that already include a table mapping the Ingress-NGINX resources: is there a reason these could not be added to the existing table?

[jnewfield]

I thought about putting these annotations in the existing table. However, the proposed annotation conversions are predicated on corresponding values. The tables contain just annotations without values while configuration snippets contain annotations and values. For example, implementing just nginx.ingress.kubernetes.io/backend-protocol to nginx.org/ssl-services would not provide the full configuration requirements for a successful conversion. This is what we saw with customer in internal case 00898038.