Create symlinks in /etc/ssh pointing to /etc/gitlab for SSH private keys

Create symlinks in /etc/ssh pointing to /etc/gitlab for SSH private keys to fix #8326 (closed)

The current Gitlab Docker image creates SSH host keys during build in /etc/ssh when installing openssh-server. These keys are not used. Instead, the SSH host keys for Gitlab are generated by the wrapper script and stored in /etc/gitlab.

Previously, the wrapper script overwrote the unused SSH public host keys in /etc/ssh with symlinks pointing to the keys used in /etc/gitlab. The SSH private keys were left untouched. Thus, there were SSH private keys in /etc/ssh that were not used and the corresponding public keys in /etc/ssh were symlinks to /etc/gitlab and the private and public keys did not match.

Since this is could be confusing for adminstrators, this commit alters the wrapper script so that the unused SSH private keys in /etc/ssh are replaced with symlinks to the private keys used in /etc/gitlab.

I did a manual build of the Docker container and started a new instance and Gitlab seems to run well.

@dustinmm80 Can you do a review?

Related issues

Closes #8326 (closed)

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