Regenerate self-signed certificates before expiration

After generating self-signed certificates for the first time, we do not regenerate them once they expire. Since these certificates are used internally, e.g. in Registry, they will cause problems. Regenerating certificates and updating the configuration can be cumbersome. The best way would be automate all or most of the process that is required for regenerating and updating certificates.

This is a follow up issue that is created in response to #1100 (closed) and aims for a new feature rather than a workaround or quick fix.