Autogenerate gitaly tls certificate
Followup to #3822 (closed)
We should support auto-generating the gitaly certificate and key, and storing them in the secrets similar to what we do for postgres ssl, and the internal registry cert.
Gitaly nodes should autogenerate this cert when tls/ssl mode is enabled, but retain support for users bringing their own certs.
The gitaly tls instructions would need to be updated for client nodes, instructing them where to find the public certificate in the case where it has been auto-generated.
Edited by DJ Mountney