Revert the CA certs sub-dir support #1031

The current July CPU docker images are held up due to the downstream docker official-images PR docker-library/official-images#22002 failing the "diff" check due to excessive size of code changes. The docker official-images maintainers highlighted the changes were not considered acceptable back in June docker-library/official-images#21636 (comment), and the feature was not pushed downstream at that time. We have now got to publishing the July images and as this feature is in this containers repo, we are thus trying to publish the same feature downstream again, and not surprisingly the maintainers point out they objected back in June.

The feature needs discussion on how best it can be supported and accepted into the docker image community.

In the mean time we need to get the July CPU images published, so we should revert the code changes for PR #955. Given this PR was merged some time ago, numerous changes have been merged since, we therefore need to do a manual revert. The main change is to the entrypoint.sh scripts, we should look at the change for this feature (#955) and manually revert those changes in the current entrypoint.sh, bearing in mind other commits for other reasons that may have been done on those files since.