WHY
As RHOAMs developer I want to ensure our codebase contains only the necessary files

WHAT
Our manifests folder is full of very old manifests that we do not need.
In fact, /manifests are only used for CVE scanning or more so - to populate RHOAMs CSV with images to scan. We can remove the /manifests folder entirely and think of alternative solution (cleaner) to generating images list on the CSV or, leave only the latest CSV within the manifests.

Also, remove the prow manifests graph check since we are no longer installing via manifests folder but instead, via the index image.

HOW
<Suggestions for how this may be solved. [Optional]

TESTS
<List of related tests>

DONE
Manifests folder is cleaned up either via finding an alternate solution to generating list of images or, by just leaving top level bundle. Manifests graph prow tests are no longer executed