Is your feature request related to a problem? Please describe.
We're using the CA issuer. The certificated it issues should have a OCSP responder URL.

Describe the solution you'd like
Add an option to the issuer resource to specify the OCSP responder URL that will be used added to issued certificates. Like #2612 but for the OCSP responder URL.

This request is only for the option, not to add an OCSP responder itself.

Additional context
I'm open for submitting a PR with this feature.

/kind feature