Add image substitutions in kustomization instead of doing a patch

[abhinavmpandey08]

Description

This PR refactors the release-manifests target to use kustomize to substitute the tink-controller and tink-servers images instead of using patches.

Why is this needed

There was a bug in the previous release-manifests target where the tink-server image wasn't being updated because its dependencies were all being met already causing it to not be re-build. This PR refactors it to not use the image patches removing the need to update these patch files.

How Has This Been Tested?

ran make release-manifests and verified that the kustomization.yaml and tink.yaml have the expected outputs

How are existing users impacted? What migration steps/scripts do we need?

No user impact

Checklist:

I have:

• updated the documentation and/or roadmap (if required)
• added unit or e2e tests
• provided instructions on how to upgrade

[codecov]

Codecov Report

Merging #617 (08f6555) into main (a0f65e9) will not change coverage.
The diff coverage is n/a.

❗ Current head 08f6555 differs from pull request most recent head 54dffbb. Consider uploading reports for the commit 54dffbb to get more accurate results

@@           Coverage Diff           @@
##             main     #617   +/-   ##
=======================================
  Coverage   44.65%   44.65%           
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  Files          61       61           
  Lines        3509     3509           
=======================================
  Hits         1567     1567           
  Misses       1860     1860           
  Partials       82       82           

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[mmlb]

I do like this way over the {manager|server}_image.yaml from before 👍