[1995518] Document known issue about scheduler misbehavior with many node images

Document URL:
N/A

Section Number and Name:
N/A

Describe the issue:
bug #1984442 shows that under certain conditions scheduling will be suboptimal if there are too many container images on a node.
This is not specific to CNV; but also impacts scheduling containers.

Suggestions for improvement:

Let's check if OCP is documenting this behavior, if not, then we should find a place to document this for all of CNV:
If they are reluctant, then we should file a known issue for CNV only

Additional information:
https://bugzilla.redhat.com/show_bug.cgi?id=1984442