Add support for specifying wellKnownPolicies when using addons

[aclevername]

Description

Closes #4158

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the userdocs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes
• (Core team) Added labels for change area (e.g. area/nodegroup) and kind (e.g. kind/improvement)

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[Skarlso]

This is so weird. It returns the resource, but then also returns the output of calling AddAllResources on the created resource. The cognitive load of this "simple" function is pretty high. I would prefer this to be separated and the caller has the responsibility to further add all resources if necessary. The createroleResourceSet doesn't suggest that this will also add all of them. It suggest construction.

[aclevername]

I think whats weird is how the resourceSets work. You use a constructor to "build" it, but its only actually build it/becomes useful after you've called AddAllResources. I could move this call further up, but its just moving the error handling around even more 🤷

[Skarlso]

Ah, well that's annoying. :D Fine, leave it as is :)

[Skarlso]

One question / note. Otherwise the generated function and logic look okay to me. I'm not sure though if anything might be missing from somewhere. In my limited understanding of the current code structure and focal points of eksctl this looks okay. :)